In a medium size bowl, cream together butter and cream cheese. Mix in whole kernel corn, cream-style corn, chiles, chopped onions, and 1/2 can of the French-fried onions. Pour mixture into a 1 quart casserole dish.
Bake in a 350 degrees F (175 degrees C) oven for 15 minutes. Remove from oven and sprinkle the remaining French-fried onions over the top of the casserole. Return to the oven and bake an additional 15 minutes.