1. Heat oven to 400°F. Cook beef in 12-inch skillet over medium-high heat until well browned, stirring often to separate meat. Pour off fat.
2. Stir soup, salsa, milk, tortillas and 1/2 cup cheese in skillet. Spoon beef mixture into 3-quart shallow baking dish. Cover baking dish.
3. Bake 30 minutes or until beef mixture is hot and bubbling. Sprinkle with remaining cheese.