HEAT oven to 400ºF.
MIX cream cheese spread, 2 Tbsp. milk and garlic powder in large bowl until blended. Add chicken, broccoli, shredded cheese and remaining milk; mix well. Spoon into 13x9-inch baking dish sprayed with cooking spray; cover.
BAKE 25 min. Meanwhile, mix cracker crumbs and butter.
STIR chicken mixture; top with crumbs. Bake, uncovered, 10 min. or until chicken mixture is heated through and crumb topping is golden brown.