Preheat oven to 400°F (200°C).

Grease a shallow 2-quart baking dish.

Brown ground beef in a large skillet over medium-high heat.

Drain off any excess grease from the cooked ground beef.

Return the browned ground beef to the skillet.

Add taco seasoning mix to the ground beef.

Add chopped and drained tomatoes to the ground beef mixture.

Add drained whole kernel corn to the ground beef mixture.

Bring the mixture to a boil over medium heat, stirring occasionally.

Pour the ground beef mixture into the prepared baking dish.

In a separate bowl, beat the egg.

Add milk to the beaten egg.

Add Mexican cornbread mix to the egg and milk mixture.

Stir until the cornbread batter is smooth.

Pour the cornbread batter evenly over the ground beef mixture in the baking dish.

Bake in the preheated oven for 25 to 30 minutes, or until the cornbread topping is golden brown and cooked through.