HEAT oven to 350°F.
BROWN meat in large skillet; drain. Add corn and salsa; cook 5 min. or until heated through, stirring occasionally. Mix cottage cheese and sour cream in small bowl.
LAYER 2 cups chips, half the meat mixture, 3/4 cup cheddar and half the cottage cheese mixture in 2-qt. casserole. Repeat layers of chips, meat mixture and cottage cheese mixture.
BAKE 35 min. Insert remaining chips around edge of casserole; top with remaining cheddar. Bake 10 min. or until cheese is melted.