Fry bacon strips in a large skillet over medium heat until crisp. Keeping the bacon and drippings in the pan, add the bell pepper, onion, and half the cilantro. Stir and cook for 1 minute. Season the chicken with garlic powder and fajita seasoning and stir into the pan. Cook mixture until chicken is no longer pink in the middle, about 20 minutes. Remove skillet from heat and sprinkle the remaining cilantro, tomato, and Monterey Jack cheese over the top of the chicken mixture. Cover and let sit until cheese melts, about 3 minutes.