Preheat oven to 350 degrees F.
In a large bowl, stir together the 2 types of corn, corn muffin mix, sour cream, and melted butter.
Pour into greased 9x13-in. casserole dish. Bake for 45 min., or until golden brown.
Remove from oven and top with Cheddar. Return to oven for 5 to 10 min., or until cheese is melted. Let stand for at least 5 min. and then serve warm.