Preheat the oven to 350°F (175°C) and lightly spray a 9×13-inch baking dish with cooking spray.
In a large bowl, combine the thawed frozen corn, creamed corn, sour cream, cornbread mix, and eggs; stir until evenly mixed.
Pour the cornbread mixture into the prepared baking dish and smooth the top. Bake for 40 minutes.
While the cornbread bakes, toss the chopped cooked chicken with the BBQ sauce in a bowl until well coated.
Remove the dish from the oven and evenly spread the BBQ chicken over the partially baked cornbread; sprinkle the shredded cheddar on top.
Return to the oven and bake an additional 10–15 minutes, until the cheese is melted and the cornbread is fully set. Let sit a few minutes before serving.