Sprinkle chicken with salt and pepper and place in a 3 to 4 quart crock pot. Top with onions and bell peppers and pour pasta sauce over all. Cover crock pot and cook on low 4 to 5 hours until chicken is thoroughly cooked. Stir well, then sprinkle with cheese and let stand 5 minutes to melt cheese. Serve over cooked pasta or rice. 8 servings.