Set the temperature of the oven to 200 C (400 F).
In a large pan, heat the ground beef containing bell pepper and chopped onions over medium flame until the veggies are tender and meat is well cooked. Remove the excess fat.
Mix in the black beans, diced tomatoes, taco seasoning, corn, salt and pepper. Cook until well warmed, it may take around 5 minutes. Take it off from the heat.
In a large-sized mixing bowl, mix the cornmeal, sugar, flour, baking powder and salt.
In a separate bowl, mix the vegetable oil, milk and eggs. Add the wet ingredients into the dry ingredients and mix until they are just combined. You can also mix in the shredded cheddar cheese.
In a greased 9 X 13 inch baking dish, evenly spread the bean mixture and the meat across the bottom.
Gently distribute the cornbread batter until it covers the entire filling.
Bake in the oven until it turns golden brown and the toothpick inserted at the center comes out clean, it may take around 30 minutes.
It's time to serve the cornbread casserole. For an extra flavour, you can top it with chopped green onions, sour cream or additional cheese.