Grease a 9x9 square baking dish and set it aside for now.
In a skillet, sauté the sausage and onion with the butter over medium-low heat until the onions are tender and the sausage is slightly browned. Transfer the sausage mixture to a plate lined with paper towels to drain any excess grease.
In your mixing bowl, combine the cornmeal, salt, and chili powder.
Stir in the eggs, milk, oil, creamed corn, and green chilies.
Add 1 cup of the shredded cheese and the sausage mixture. Fold it together.
Spread the batter into your prepared baking pan. Sprinkle with the remaining cheese.
Bake for 35-40 minutes, or until it tests done with a toothpick in the center. If it begins to get too brown on top while it is baking, simply cover it with some aluminum foil for the remainder of the baking time.