Heat oven to 400°F. In 10-inch skillet, cook beef over medium-high heat, stirring frequently, until thoroughly cooked; drain. Stir in salsa, kidney beans, tomatoes, corn, chili powder and cumin. Cook 3 to 4 minutes, stirring occasionally, until thoroughly heated.
Meanwhile, make cornbread mix as directed on package using milk and, if required, margarine and egg. Spoon cornbread batter around outside edge of ungreased 12x8-inch (2-quart) glass baking dish. Spoon hot beef mixture into center. (Casserole will be full.)
Bake 18 minutes. Sprinkle with cheese; bake 4 to 5 minutes longer or until cheese is melted and cornbread is deep golden brown. Just before serving, sprinkle with green onions.