Preheat the oven to 425 degrees F.
Place sliced chicken, bell peppers, and onions onto a large baking sheet.
In a small bowl, mix together the chili powder, cumin, oregano, paprika, and salt.
Sprinkle spice mixture over chicken and veggies and then drizzle with olive oil. Using your hands or a large spoon, mix everything together.
Place in preheated oven and bake until chicken is cooked through, about 25 minutes.
Serve with tortillas, sour cream/Greek yogurt, lime, salsa and guac. Enjoy!