Saute onion in large pot with margarine until soft. Add canned chilies, jalapeno, corn and garlic powder, stir. Add liquids and rice, cover, lower heat and cook to package specifications, approximately 20 minutes.
Preheat oven to 400 degrees Fahrenheit.
When rice is cooked and all the liquids are absorbed remove from heat and stir to evenly distribute ingredients.
Stir in sour cream and 1 cup vegan cheese, mix well. Transfer to casserole dish greased with margarine, and bake for 20 minutes.
Top with remaining cheese and bake an additional 5 minutes until cheese is melted (as much as possible). Allow to cool slightly and serve.