If fillets are large, cut into 5 serving pieces.
Mix sour cream, lemon juice, and chili powder. Dip fish into sour cream mixture, then coat with chips. Place in generously greased 13x9 baking dish.
Pour butter over fish. Cook uncovered at 500 degrees F until fish flakes easily with a fork, about 10 to 12 minutes.
Can be served with sliced avocado and tomato halves.