I'm not sure where I originally got this recipe, but it's been in my file for awhile now.
1 pound hamburger
1 medium onion
1 can stewed tomatoes
1 pkg. taco seasoning
1 lb. cheddar cheese (1 lb. seems like a lot; I used an 8 oz. package)
Brown hamburger and onion. Add stewed tomatoes and taco seasoning and simmer for 10 minutes. Layer meat, tortillas and cheese 2-3 times in 9 x 13 pan. Bake at 350 degrees for 1/2 hour, uncovered.