01 - Preheat oven to 375°F. In a large skillet over medium heat, cook ground beef, diced onion, and minced garlic until the beef is browned and onion is soft.
02 - Add drained kidney beans, drained corn, and salsa or diced tomatoes to the skillet. Stir well and simmer for 5 minutes.
03 - Transfer the beef mixture into a baking dish. Evenly top with shredded cheddar cheese and, if desired, sprinkle crushed tortilla chips or cornbread crumbles over the cheese.
04 - Bake in the preheated oven for 15 to 20 minutes, until the cheese is melted and the casserole is bubbling.