A few years ago, my paternal grandmother gave me (as well as many of her other granddaughters) a folder containing some of her favorite recipes. This is one of them. It's super simple, and takes only minutes to put together. Like many casseroles, it's not exactly the prettiest thing in the world, but it's yummy.
Here is the recipe exactly as Grandma wrote it.
Mix together 1 large can chili con carne w/beans and 2 cans cream of mushroom soup. Layer in casserole with large flour tortillas and grated cheese, ending with cheese. Bake for 30 minutes at 350 degrees.
When I made this, I only needed a little bit. Grandma would make this large enough to feed a crowd, but I only had my little family to feed. So I used one regular-sized can of chili and one can of soup, and layered the ingredients in a 9-inch round cake pan, then cooked it for 20 minutes. The soft-taco size tortillas were the perfect size to fit in my cake pan.