Dorito Chicken

2 cups cooked chicken, cubed
1 8 ounce carton sour cream
1/2 onion chopped
1 teaspoon chili powder
1/2 teaspoon salt
1/2 teaspoon pepper
1/2 teaspoon garlic powder
1/2 cup grated cheddar cheese
1/2 cup grated mozzarella cheese
1 medium size bag of Doritos, crushed

Cover the bottom of a lightly sprayed 2 quart casserole dish with half the crushed Doritos. Mix the rest of the ingredients together except cheese and place on Doritos. Put remaining Doritos on top and cover with cheeses. Bake at 350F for 30 to 40 minutes until bubbly.