PREHEAT oven to 400°F. Mix barbecue sauce and mustard in pie plate or shallow dish; set aside. Mix coating mix and garlic powder in separate pie plate or shallow dish.
DIP chicken in barbecue sauce mixture, then in coating mixture, turning over to evenly coat both sides. Place in single layer in foil-lined 15x10x1-inch baking pan. Discard any remaining coating mixture.
BAKE 20 min. or until chicken is cooked through.