1. Peel shrimp; devein, if desired. Coarsely chop shrimp. Preheat oven to 375°.
2. Melt butter in a large skillet over medium-high heat; add onion, and sauté 2 to 3 minutes or until tender. Stir in shrimp, and sauté 2 to 3 minutes or just until shrimp turn pink. Remove from heat, and stir in green chiles.
3. Whisk together corn, sour cream, and eggs in a large bowl until blended; whisk in cornbread mix just until blended. Stir shrimp mixture and 1 1/2 cups shredded Cheddar-Jack cheese into corn mixture just until blended; pour into a lightly greased 13- x 9-inch baking dish, and sprinkle with remaining 1/2 cup shredded cheese.
4. Bake at 375° for 45 minutes or until a wooden pick inserted in center comes out clean. Let stand 10 minutes before serving.
Note: For testing purposes only, we used Martha White Cotton Country Buttermilk Cornbread Mix.