In a large skillet, cook ground beef, onion, and green bell pepper over medium heat until the beef is browned and the vegetables are tender. Drain excess grease.

Stir in chili powder, black pepper, cumin, tomato sauce, and kidney beans into the skillet with the beef mixture. Let it simmer for about 5 minutes, stirring occasionally.

Preheat your oven to 350 degrees F (175 degrees C). Lightly grease a 9x13-inch baking dish.

In a bowl, mix together the cornbread mix, milk, and egg until well combined.

Spread the cornbread batter evenly into the bottom of the prepared baking dish.

Pour the beef and bean mixture over the cornbread layer, spreading it out evenly.

Bake in the preheated oven for 20 minutes, or until the edges of the cornbread are golden brown and the center is set.

Sprinkle the shredded cheddar cheese over the top of the casserole and return to the oven. Bake for an additional 5 to 10 minutes, or until the cheese is melted and bubbly.