Prepare the corn bread. Mix the corn muffin mix, egg, sour cream, corn, and diced chiles. Pour into a greased, 12" cast iron skillet. Put in the oven and bake for 20 minutes, until the top is lightly browned.
While the cornbread is cooking, cook the chopped onion and ground beef in a skillet until the beef is brown. Drain off the fat.
Add the cumin, chili powder, garlic powder, salt, red pepper flakes, and water to the ground beef, and simmer until the water is mostly gone. Add the cheese sauce and mix to combine.
Remove the cornbread from the oven and let it cool for a few minutes. Carefully spread the ground beef on top of the cornbread, then top with the cheddar cheese. Cover with aluminum foil and return to the oven for 20 minutes. After 20 minutes, remove the foil and bake for another five minutes, uncovered.