Cook beef until browned and crumbled. Drain grease and stir in tomatoes, corn, sour cream, and chili powder. Set aside.
In a 9 x 13 inch or similar size pan, spread the crushed chips, then layer half of the beef mixture, half thecheese, then remaining beef and cheese.
Bake at 350° F for 20 - 25 minutes or until heated through.