Mix seasonings in a small bowl.
Heat oil in a pot. Add onion, cook 4–5 minutes. Add garlic, cook 1 more minute.
Add ground beef, season with spice mix, cook until browned.
Stir in broth, diced tomatoes, and beans. Bring to boil, then cover and simmer 30 minutes.
Uncover and cook 10–20 minutes until chili is thick and saucy.
Preheat oven to 400°F. Prepare cornbread batter with milk and egg.
Spread chili evenly in a 2.3 qt (11x7 in) casserole dish. Top with cornbread batter.
Bake 15–20 minutes until golden brown.
Let rest 15 minutes before serving.