Preheat oven to 375. In large skillet, brown ground beef, onion and garlic over medium high heat until meat is brown and onion is tender; drain. Reduce heat to medium low. Stir in corn, tomato sauce, green chilies, chile powder and salt. Remove from heat.
In small bowl beat sour cream and egg until well blended. Stir in 1 cup cheese. Combine sour cream mixture with ground beef mixture. Spoon into lightly greased 9x13 pan.
In medium bowl, prepare corn bread mix according to package directions. spread corn bread batter ovedr casserole. Sprinkle with remaining 1 cup cheese. Bake, uncovered, 30 minutes or until heated through and corn bread topping is golden brown. serve warm.