HEAT oven to 400°F.
ADD Parmesan to coating mix in shaker bag; shake gently to combine. Coat chicken with Parmesan mixture, then bake as directed on package.
MEANWHILE, cook onions and dressing in large skillet on medium-high heat 4 min. or until onions are crisp-tender. Stir in tomatoes; cook 2 to 3 min. or until heated through, stirring occasionally. Stir in basil. Keep warm.
TOP chicken with sauce and cheese.