Prepare the Filling:
Preheat oven to 375°F (190°C). In a large skillet over medium heat, cook ground beef with onion, bell pepper, and garlic until beef is browned and vegetables are softened. Drain excess fat.
Add Seasoning and Veggies:
Stir in diced tomatoes, tomato sauce, corn, taco seasoning, salt, and pepper. Simmer for 5–10 minutes until mixture is thickened slightly. Remove from heat and stir in 1/2 cup shredded cheese.
Prepare Cornbread Topping:
In a medium bowl, whisk together cornmeal, flour, sugar, baking powder, and salt. In another bowl, whisk milk, oil, and eggs. Combine wet and dry ingredients until just mixed.
Assemble the Pie:
Spread the meat filling evenly in a greased 9x13-inch baking dish. Pour the cornbread batter evenly over the filling. Sprinkle remaining 1/2 cup shredded cheese on top.
Bake:
Bake for 25–30 minutes, or until cornbread is golden brown and a toothpick inserted in the center comes out clean.
Serve:
Let cool for 5 minutes before slicing. Serve warm, optionally with sour cream, salsa, or guacamole.