Grease casserole dish.
Tear tortillas into bite-sized pieces. Arrange half of the tortillas into baking dish; top with half of the cheese, half the corn, and half the onions. Repeat layering with the remaining half of the cheese, corn, and onions.
Stir together buttermilk, eggs, and chili peppers. Gently pour over tortilla mixture. Bake uncovered in a 325 degree oven for about 30 minutes or until knife inserted near centre comes out clean. Serve warm.