Cheesy Chicken Fajita Casserole
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This one-pan Chicken Fajita Casserole is a go-to macro-friendly 30-minute meal. Packed with shredded chicken, peppers & onions, corn tortillas, LOTS of gooey cheese, and fajita spices, it’s a protein-packed, low-calorie dinner the whole family will love!
I was browsing Eating Well recently when a “Chicken Fajita Casserole” recipe, specifically its impressive protein-to-calorie ratio, got my attention. So naturally, I had to test it out and add my own twist.
While the original called for sliced chicken thighs and a long list of individual spices, I decided to lean on my favorite weeknight shortcut: the rotisserie chicken. I shredded up that juicy pre-cooked meat and tossed it with my favorite gluten-free fajita seasoning blend because I love working smarter, not harder.
The rest of this skillet is classic fajitas meets a cheesy, indulgent baked casserole—think colorful bell peppers and onions, diced tomatoes and green chilies, corn tortillas, lime juice, and a generous amount of melty cheese on top.
Now, let’s talk numbers. One serving delivers a whopping 34 grams of protein, only 450 calories, and the whole thing comes together in one pan in about 30 minutes flat. If you’re looking for more easy, chicken-fajita-inspired recipes that lean a bit more classic than casserole, you have to try my Easy Chicken Fajita Nachos or my Blackstone Chicken Fajitas next!
Why You’ll Love It
- Super simple, one-pan recipe. Since we’re using rotisserie chicken and a skillet that goes from the stove straight to the oven, prep and clean-up are a breeze.
- Perfect for macro-trackers. With over 34 grams of protein and less than 450 calories per serving, it’s a rare comfort food that helps hit your goals without feeling like you’re eating diet food. It’s a meal you can feed the whole family without complaints!
- Naturally gluten-free. By sticking to 100% corn tortillas and a gluten-free fajita seasoning blend, this casserole is a nutritious, inclusive option that doesn’t sacrifice an ounce of that authentic Tex-Mex flavor.
Ingredient Notes
- Oil. I use avocado oil for sautéing, but you can use whatever neutral oil you like.
- Bell peppers. I go with a mix of green and red, but feel free to mix and match with orange or yellow. The more colors, the better!
- Onion. White onions are the most traditional choice for fajitas, but yellow onions are great too. That’s what I happened to have on hand.
- Fajita seasoning. You can’t beat the flavor and quality of Siete, but if you can’t find it, McCormick Organics or Kinders are solid swaps. You can also DIY a quick mix with chili powder, cumin, smoked paprika, garlic powder, salt, and pepper, or use my Easy Chicken Taco Seasoning here.
- Shredded chicken. I shred the breast from a rotisserie chicken, but if you enjoy a richer, juicier flavor, go ahead and shred some thigh and leg meat as well.
- Diced tomatoes with green chilies. You can either grab a can of Ro-Tel or combine a can of diced tomatoes with a 4-oz can of diced green chilies. Whatever you use, drain off the juices so your casserole doesn’t get soggy.
- Lime juice. A squeeze of fresh lime juice is the secret to brightening up the Tex-Mex flavors.
- Tortillas. I slice the tortillas into strips and stir them right into the skillet to soak up the juices, giving the casserole a thick, enchilada-like feel. I use corn tortillas to keep the casserole gluten-free, and I prefer the texture over flour tortillas.
- Mexican cheese blend. I grab a pre-shredded bag to save time, but if you want a more Mexican restaurant-quality cheese pull, shredding your own blend of Monterey Jack, Sharp Cheddar, and a little Asadero is the way to go. You’ll need at least 1 cup, but this is a “cheesy” fajita casserole after all, so feel free to add an extra ½ cup.
How to Make the Best Chicken Fajita Casserole
Step 1: Prep the oven. Preheat your oven to 400°F.
Step 2: Sauté the vegetables. Meanwhile, heat the oil in a large, ovenproof skillet over medium heat, then add your peppers and onions and let them cook, stirring often, just until they start to get a little fragrant and lose their crunch.
Step 3: Bloom the spices. Reserve 1 tbsp of the fajita seasoning, and sprinkle the rest over the peppers and onions. Continue cooking and stirring for about 4 more minutes.
Step 4: Add the chicken. Toss your shredded chicken with the reserved seasoning, then add it to the skillet along with the drained diced tomatoes and green chilies, and let everything cook for a couple more minutes.
Step 5: Finish assembling. Turn off the heat, then stir in the fresh lime juice and tortilla strips before sprinkling the cheese over the top.
Step 6: Bake. Pop the whole skillet into the oven for 15 minutes or until the cheese is completely melted, golden, and bubbly. Enjoy!
Recipe Tips and FAQs
- No ovenproof skillet? Just sauté everything in a regular pan, then transfer the mixture to a 9×13-inch ceramic, stoneware, or glass baking dish, top with cheese, and pop it in the oven.
- Don’t rush the “bloom.” When you add the fajita seasoning to the pan, they’ll start to sizzle, and that’s a good thing! Toasting the spices in oil really wakes them up, infusing a deeper, smokier flavor throughout the dish that just stirring them in can’t match.
- If you want the tortilla strips to have more bite and less of that soft, enchilada-style texture, you can firm them up in a dry skillet for 15–30 seconds or quickly toast them in the air fryer for a few minutes at 375°F before stirring them into the skillet.
- If you have time, let your shredded cheese sit on the counter for 10 minutes before topping the casserole. Room temperature cheese melts so much better than cold cheese from the fridge.
Customize Your Casserole
Here are a few ways you can put your own signature spin on this easy, cheesy fajita skillet:
- Extra veggies – Sauté sliced mushrooms or zucchini with the peppers and onions, or toss in a handful of spinach toward the end of the sauté.
- Add beans – For extra fiber and protein, stir in a drained can of black beans or pinto beans with the seasoned shredded chicken.
- Swap in beef – This recipe is also great with shredded beef. If you have leftovers from recipes like my Cuban-Style Shredded Beef, Southwest Pot Roast, or Mexican Picadillo, they’ll fit right in! 🙂
- Add more spice – I’m a medium-heat kind of gal, but if you like it spicier, sauté some sliced jalapeños with the peppers and onions, or add a dash of cayenne pepper to your fajita seasoning.
- Add rice – You can easily turn this into a cheesy chicken fajita and rice casserole by stirring in 1 to 2 cups of cooked rice with the chicken instead of the tortillas.
No worries. Any pre-cooked chicken works. If you have leftover grilled chicken breasts or even poached chicken, just shred or dice it up. The goal is to keep it tender and juicy so it can soak up all those zesty fajita spices.
To keep things high-fiber and high-protein, I love serving this casserole topped with sliced avocado, fresh cilantro, a blend of salsas (like my Red Salsa and Trader Joe’s Corn & Chile Salsa), and a big dollop of sour cream or plain Greek yogurt (it tastes just like sour cream but with more protein!).
You could also scatter some pickled jalapeños, radishes, or even some of this zesty Fiesta Salad on top. Seriously, the sky is the limit!
You can sauté the veggies and mix in the seasoned chicken and tomatoes & green chiles up to 24 hours in advance. Store the mixture in the fridge, then add the lime juice, tortilla strips, and cheese right before you’re ready to bake.
Storing & Freezing
Storing: Once your skillet has cooled to room temperature, transfer leftovers to an airtight container and refrigerate for 3 to 4 days. When you’re ready for round two, just pop a portion in the microwave for 60 to 90 seconds.
Freezing: The tortillas may get a little too soft after freezing and thawing, so I wouldn’t recommend freezing this one.
More High-Protein Chicken Casserole Recipes
- Swiss Chicken Casserole
- Chicken Vegetable Casserole
- Chicken Spinach Casserole
- Butternut Squash Chicken Casserole
- Marry Me Chicken Casserole
If you love this Baked Chicken Fajita Casserole recipe, I would be so grateful if you could leave a 5-star 🌟 rating in the recipe card below. I love reading your comments and feedback!
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Cheesy Skillet Chicken Fajita Casserole
Equipment
- Large oven-proof skillet
Ingredients
- 3 tbsp avocado oil
- 1 large green bell pepper ,seeded and sliced into strips
- 1 large red bell pepper ,seeded and sliced into strips
- 1 medium onion ,halved and sliced
- 1 packet Siete fajita seasoning ,divided
- 2½ cups shredded rotisserie chicken breast
- 14.5 oz diced tomatoes and green chilies ,drained
- 1 tbsp fresh lime juice
- 6 corn tortillas 6" size, halved and sliced into strips
- 1 cup shredded Mexican cheese blend
- *Optional: chopped fresh cilantro for garnish
Instructions
- Preheat oven to 400 degrees F.
- In a large, oven-proof skillet, heat the avocado oil over medium heat.
- Add the sliced peppers and onion. Cook, stirring often, for 2 minutes.
- Reserve 1 tbsp of the fajita seasoning and sprinkle the rest over the peppers and onion. Continue cooking, stirring often, for about 4 minutes more.
- In a medium-sized bowl, toss the shredded rotisserie chicken with the reserved fajita seasoning and add it to the skillet. Add the drained diced tomatoes and green chilies and cook for a couple more minutes, stirring occasionally.
- Turn off the heat, then stir in the lime juice, followed by the tortilla strips. Make sure everything is well mixed, then sprinkle the cheese over the top. Bake for 15 minutes until the cheese is melted and bubbly.
Notes
- No ovenproof skillet? Just sauté everything in a regular pan, then transfer the mixture to a 9×13-inch ceramic, stoneware, or glass baking dish, top with cheese, and pop it in the oven.
- Don’t rush the “bloom.” When you add the fajita seasoning to the pan, they’ll start to sizzle, and that’s a good thing! Toasting the spices in oil really wakes them up, infusing a deeper, smokier flavor throughout the dish that just stirring them in can’t match.
- If you have time, let your shredded cheese sit on the counter for 10 minutes before topping the casserole. Room temperature cheese melts so much better than cold cheese from the fridge.
Nutrition
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