Preheat oven to 400°F (200°C).
In a skillet, cook ground beef over medium heat until browned. Drain excess fat.
Add onion and garlic to the skillet. Cook until softened.
Stir in chili powder, cumin, salt, and pepper. Cook for another minute.
Add kidney beans, diced tomatoes, and corn. Simmer for 10 minutes.
Pour the chili mixture into a baking dish.
In a mixing bowl, combine cornmeal, flour, sugar, baking powder, and salt.
Add milk, beaten egg, and vegetable oil to the dry ingredients. Mix until just combined.
Spread the cornbread batter evenly over the chili.
Bake in the preheated oven for 20-25 minutes, or until the cornbread is golden brown.
Let cool for a few minutes before serving.