1. In a bowl, add the chili and tomato sauce and stir to combine.
2. Add a layer of the chili mixture to the bottom of a 9x9-inch (23x23-cm) baking pan. Top with a layer of tortillas, a layer of chili, and sprinkle with cheese.
3. Repeat until all ingredients are used, making sure the top layer is cheese.
4. Cover and refrigerate for at least 3 hours, up to overnight.
5. Preheat oven to 350˚F (180˚C).
6. Remove the casserole from the refrigerator and let sit for 10 minutes on your counter.
7. Poke three toothpicks in the casserole, and cover with tin foil, so that the foil doesn’t touch the cheese layer.
8. Bake for 30-40 minutes, or until cheese is melted.
9. Cut and serve.