Preheat oven to 375 degrees. Coat a 9″ 2-quart casserole dish or oven-proof 9″ glass bowl, or a 9″ X 12″ rectangle, with cook spray and set aside.
For the tamale filling: In a large nonstick pan over medium heat, add the ground beef, onions, and garlic. Cook stirring often, breaking up beef until meat is browned. Pour into a colander to drain the fat. Add back to pan.
Stir in beans, corn, tomatoes, cheese, chili powder. salt and pepper. Cook for 5 minutes. Remove from heat.
To make cornbread topping: Add to a mixing bowl 1½ cups water and cornbread mix. Mix by hand until lumps disappear.
Pour the tamale mixture into the casserole dish. Spread evenly. Top with cornbread batter and spread evenly.
Bake for 30-35 minutes until a toothpick inserted into the cornbread comes out clean.
Cool a bit and cut into 8 slices. This dish will keep for several days in the refrigerator and freezes great.