Prepare and bake the cornbread using package directions. Let stand until cool.
Combine the mayonnaise, sour cream, and dressing mix in a bowl; mix well.
Toss the tomatoes, bell pepper, and green onions in a bowl.
Crumble 1/2 of the cornbread into a large salad bowl or rectangular cake pan. Layer with 1 can of the pinto beans, 1/2 of the tomato mixture, 1 cup of the cheese and 1 can of the corn. Spread with 1/2 of the mayonnaise mixture. Repeat the layers with the remaining ingredients. Chill, covered for two hours.