Cook the ground beef: In a large skillet, heat a tablespoon of oil over medium heat. Add the ground beef and cook, breaking it up with a spoon, until browned and fully cooked, about 5-7 minutes. Drain any excess fat.
- Add the vegetables and seasonings: Add the chopped onion and minced garlic to the skillet and cook for 3-4 minutes, until softened. Stir in the chili seasoning mix, cumin, chili powder (if using), salt, and pepper. Mix well to coat the beef and vegetables in the spices.
- Add the beans and tomatoes: Stir in the kidney beans, diced tomatoes (with juices), tomato sauce, and beef broth. Bring to a simmer, then reduce the heat and let it simmer for 10-15 minutes, allowing the flavors to meld together and the sauce to thicken.
- Assemble the casserole: Preheat the oven to 375°F (190°C). In a 9×13-inch baking dish, spread a layer of Fritos chips on the bottom. Pour the chili mixture over the chips, spreading it evenly.
- Top with cheese and Fritos: Sprinkle the shredded cheddar cheese over the chili, then add a handful of additional Fritos chips on top for extra crunch.
- Bake: Place the dish in the preheated oven and bake for 15-20 minutes, or until the cheese is melted and bubbly.
- Serve: Remove the casserole from the oven and let it cool for a few minutes before serving. Garnish with additional Fritos chips and chopped green onions, sour cream, or fresh cilantro if desired.