Heat oven to 350F. In 9-inch ovenproof skillet, cook meat, onion, bell pepper and garlic until meat browns, about 8 minutes; drain fat. Stir in salt, tomatoes, chili powder, cumin and corn. Cook until juices thicken, about 4 minutes. Meanwhile, prepare corn muffin mix according to package. Spread batter over meat mixture. Sprinkle with cheese and scallion. Bake until corn bread is done, about 20 minutes. Cut into wedges or spoon onto plates.