Combine lime juice, olive oil, garlic, cumin, chili powder, salt, and pepper and pour over chicken in an airtight container. Refrigerate for at least 30 minutes. For best results, marinade for 2 hours rotating the container every 30 minutes to coat each chicken piece in marinade.
Preheat oven to 400.
Lightly spray 9x13 baking dish with olive oil cooking spray.
In a large bowl, combine bell peppers, onions, and diced tomatoes. Pour chicken and marinade over and stir well. Pour contents into baking dish.
Bake for 20 to 25 minutes until chicken is no longer pink.
Serve on warmed tortillas with fresh salsa.