HEAT oven to 400ºF.
COAT chicken with coating mix as directed on package. Place in 13x9-inch baking dish sprayed with cooking spray. Combine potatoes, onions, bacon and 1/4 cup dressing; spoon around chicken.
BAKE 40 min. or until chicken is done (165°F). Meanwhile, combine tomatoes, cheese and remaining dressing.
SPOON tomato mixture over chicken. Bake 5 min. or until cheese is melted.