Preheat oven to 400 degrees F (200 degrees C).

In a large skillet, cook ground beef and chopped onion over medium heat until beef is no longer pink; drain any excess grease.

Measure 1/2 cup of the green chile sauce and set aside.

Add the remaining green chile sauce to the skillet with the ground beef.

Stir in the taco seasoning and water. Bring the mixture to a boil.

Reduce heat and stir in frozen corn and sliced black olives.

Spoon the beef mixture into a greased deep-dish pie plate or a 1.5-quart casserole dish.

Sprinkle 1 cup of shredded cheddar cheese over the beef mixture.

In a separate bowl, combine the cornbread mix, egg, and the reserved 1/2 cup of green chile sauce; mix well until smooth.

Spoon the cornbread mixture evenly over the cheese layer.

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

Remove from oven and sprinkle the remaining shredded cheddar cheese over the top.

Let stand for a few minutes before serving. Serve hot.