Slow Cooker Chicken Prepared spaghetti sauce makes preparing this favorite Italian standby a breeze. Just add chicken, mushrooms, onion, and green pepper and you are on your way! Serve over angel hair pasta. INGREDIENTS: 6 skinless, boneless chicken breast halves 1 (28 ounce) jar spaghetti sauce 2 green bell pepper, seeded and cubed 8 ounces fresh mushrooms, sliced 1 onion, finely diced 2 tablespoons minced garlic DIRECTIONS: 1.Put the chicken in the slow cooker. Top with the spaghetti sauce, green bell peppers, mushrooms, onion, and garlic.2.Cover, and cook on Low for 7 to 9 hours.