In a medium bowl, mix together the green chiles, corn, and onion.
Place the mixture in an 8x8 inch baking dish.
In a medium saucepan, melt the butter over medium heat. Stir in the flour, and cook for 1 minute. Gradually stir in the milk, and cook until thickened. Remove from heat, and stir in the salt and pepper.
Pour the sauce over the green chile and corn mixture. Top with the cheddar cheese, and sprinkle with the crushed corn chips.
Bake in the preheated oven for 25 minutes, or until cheese is melted and bubbly. Serve hot.
Interesting Facts
This casserole can be made ahead of time, and refrigerated or frozen for later use.
For a spicier version of this casserole, try adding diced jalapenos or other hot peppers.
This casserole can also be made with canned, drained corn, or fresh corn kernels.