Use a large skillet coated with nonstick cooking oil spray, and cook the meat, onion, and garlic over medium heat, until the meat is done, about 7 minutes.
Drain any excess grease, and add the tomato sauce, salsa, cumin, chili powder, and corn, mixing well.
Coat a 13 x 9 x 2 inch baking pan with nonstick cooking spray. Layer one-third of the meat mixture, and cover the mixture with one third of the tortilla strips.
Repeat the layers, starting with a fourth of the remaining meat mixture, then topping with a third of the tortilla strips. Continue layering, ending with the meat mixture, and cover and bake for 35 to 40 minutes, or until thoroughly heated.
Sprinkle with the cheese, and continue cooking for another 5 minutes, or until the cheese is melted. Cool for 5 minutes, and serve.