In a Dutch oven or large kettle, cook the beef, onions and green peppers over medium heat until meat is no longer pink; drain. Stir in the tomatoes, beans, corn, tomato sauce and taco seasoning. Bring to a boil. Reduce heat; simmer, uncovered, for 30 minutes (mixture will be thin).
In each of two greased 13-in. x 9-in. x 2-in. baking dishes, layer 5 cups of chips and 4-2/3 cups of meat mixture. Repeat layers. Top each with 4 cups of chips and 2 cups of cheese.
Bake, uncovered, at 350° for 20-25 minutes or until golden brown. Yield: 2 casseroles (15 servings each).