Preheat oven and sheet pan to 400℉.
In a mixing bowl, combine the oil, Kosher salt, black pepper, smoked paprika, chili powder, cumin, dried oregano, garlic powder, and cayenne pepper (optional). Stir to combine and set aside while you prep the vegetables and chicken.
Slice the onion and peppers, set aside. Slice the chicken and set aside.
In a mixing bowl, add the sliced chicken and peppers. Pour the seasoned oil over and toss to coat well. The mixture will be dry.
Remove the preheated sheet pan from the oven and place it on a heat-resistant surface. Add the coated meat and vegetables to the pan and spread them out.
Bake for 25-30 minutes, or until the chicken is cooked through and the vegetables are tender.
Serve with tortillas, cilantro, and a fresh squeeze of lime.