HEAT oven to 400ºF.
PLACE chicken in 13x9-inch baking dish; surround with mushrooms and peppers. Top chicken with tomatoes and shredded cheese. Bake 30 min. or until chicken is done (170ºF).
MEANWHILE, prepare Kraft Dinner as directed on package, using the Sensible Solution directions.
SERVE chicken and vegetables with Kraft Dinner.