Preheat oven to 400 degrees F.
Chop sweet potatoes (leaving skin on...good nutrients in there) into small cubes.
Spread cubed sweet potatoes onto a baking sheet and toss with 1 tbsp olive oil.
Sprinkle with kosher salt and roast for 25 minutes.
While potatoes are cooking, spray a medium skillet with olive oil and heat to medium heat.
Saute pancetta and onion until onion is soft and pancetta starts turning a little golden brown.
Transfer to a small bowl to cool.
Wipe out skillet with a paper towel and add walnuts to the pan.
Toast walnuts on med/high heat stirring constantly, until fragrant and lightly golden (be careful not to burn).
Cool nuts and set aside.
When potatoes are done, cool to room temperature, then assemble your salad.
Place greens in a large bowl, top with sweet potatoes, pancetta mixture, goat cheese and walnuts.
Right before serving, drizzle with desired amount of balsamic vinaigrette and toss to mix.