Preheat oven to 350°. In a large skillet, cook ground beef over medium heat until no longer pink, breaking it into crumbles; drain. Stir in enchilada sauce and salsa; set aside. , Place 2 tortillas, overlapping as necessary, in the bottom of a greased 13x9-in. baking dish. Cover with a third of the meat mixture. Top with 1 cup corn; sprinkle with 1-1/3 cups cheese. Repeat layers once, then top with remaining tortillas, meat and cheese. , Bake, uncovered, 30 minutes or until bubbly., Freeze Option: Cover and freeze unbaked casserole. To use, partially thaw in refrigerator overnight. Remove from refrigerator 30 minutes before baking. Preheat oven to 350°. Bake casserole as directed, increasing time as necessary to heat through and for a thermometer inserted in center to read 165°.