Preheat oven to 350?F In a large bowl, stir together two cans of corn. Corn muffin mix, sour cream, and melted butter. Pour into a greased 9x13-inch casserole dish. Bake uncovered for 45 minutes or until golden brown. Remove from oven and top with cheddar cheese. Return to oven for 5 to 10 minutes, or until cheeses melted. Let stand for at least 5minutes and then serve warm.