3 cups onions, chopped
1 (18 oz) bottle of barbecue sauce (Sweet Baby Ray's, Bullseye or your favorite)
1 (8 oz) can tomato sauce
2 tablespoons Worcestershire sauce
Place onions in a microwave safe bowl and cook in the microwave for 3 minutes to soften. Add cooked onions to crock-pot. Stir in barbecue sauce, tomato sauce, and Worcestershire sauce. Mix well. Add the chicken breasts and submerged into sauce. Cover and cook on high heat 2 hours or on low heat 4 hours.