Preheat oven to 400 degrees F.
In a small mixing bowl mix together the chili powder, salt, cumin, oregano, onion powder, garlic powder and black pepper.
Slice green, red, yellow peppers and onions.
Spray a baking sheet with no stick cooking spray. Add peppers and onions to it.
Cut chicken into long thin strips and place on top of the veggies.
Sprinkle the chicken with 1/2 of the seasoning. (Save the other 1/2 for the next time you make these.)
Bake for 25 minutes, mixing half way through.