Preheat oven to 350°F and grease a 9x9-inch baking dish.
In a large bowl, mix together both cans of corn, sour cream, melted butter, and corn muffin mix until well combined.
Pour the mixture into the prepared baking dish and spread evenly.
Bake for 45-50 minutes, or until the top is golden brown and the center is set.
Let cool for 5 minutes before serving.