Heat a 12-inch oven-safe skillet (cast iron preferably) over medium-high. Add the ground beef and cook 8 minutes, breaking it up into small pieces. When no pink remains, add the onion, bell pepper, and jalapeño. Cook another 5 minutes.
Add the garlic, chile powder, cumin, coriander, and salt. Stir well to coat the meat and veggies with the spices, cooking for about 1 minute, until fragrant.
Stir in the beans, corn, and tomatoes, mixing well. Cook just another few minutes to meld flavors. Remove from heat and stir in half of the shredded cheese.
To make the cornbread, in a bowl whisk together the cornmeal, flour, sugar, baking powder, baking soda, and salt. Add the buttermilk, eggs, and sour cream, stirring until evenly incorporated and no dry bits remain.
Smooth out the top of the filling in the pan (or transfer to casserole if needed), then dollop on the cornbread batter. Spread to the edges of the pan.
Bake for 20 minutes, until cornbread is golden brown and a toothpick inserted into the middle comes out clean.
Let cool 10 minutes before serving.
Notes
If baking in a 9x13-inch casserole, lightly coat with nonstick spray before adding filling and cornbread batter.