In a cast iron skillet over medium-high heat, add oil, onion and garlic. Let cook for 3 minutes then add ground beef. Cook and crumble until no longer red.
Preheat oven to 400degF.
Reduce heat to medium. Add in corn, black beans, crushed tomatoes, jalapenos, chili powder, cumin, salt, and red pepper flakes. Stir to combine.
In a mixing bowl, combine ingredients as directed on the corn bread mix. Add in cheese and stir to combine. Spoon cornbread mix over chili and spread to an even layer. Cover with foil. Bake for 45 minutes.
Remove foil and cook another 5 minutes. Remove from oven and let sit for at least 5 minutes before spooning out. Serve with dollop of sour cream on top.