1. Coat large skillet with cooking spray. Preheat skillet over medium-high heat. Add chicken and cook until lightly browned on all sides, turning as needed (2-3 minutes per side).
2. Add pepper, onion, and mushrooms to the pan. Saute until just browned (3-4 minutes).
3. Stir in tomatoes, water, Italian seasoning, and pepper. Bring to boil. Reduce heat, cover, and simmer, stirring occasionally, until the largest piece of chicken reaches a minimum internal temperature of 165 degrees F (15-20 minutes).
4. Remove chicken from skillet, set aside, and cover to keep warm. Continue to simmer sauce, uncovered, until thickened (4-6 minutes).
5. Top chicken with sauce to serve.