Mix together onion, beans, corn, zucchini, bell pepper, chilies, 1 teaspoon chili powder, and cumin. Spread mixture into a cooking spray coated 9 inch pie plate.
Combine baking mix, 1/2 teaspoon chili powder, and cheese. Whisk together milk, egg, and egg whites and whisk into dry mixture. Spoon batter into pie plate and bake 35 to 40 minutes. Let rest 5 minutes before serving.