1Heat oven to 400° F. In a 13x9-inch glass baking dish (3-quart), place the tamales (husked) so the bottom is completely covered (you may have to cut some in half).
2In medium bowl, mix chicken and salsa; spoon over tamales. Sprinkle with cheese. Cover dish tightly with foil sprayed with cooking spray to avoid sticking.
3Bake 25 to 35 minutes or until bubbly and cheese is partially melted. Remove from oven; uncover. Drop sour cream by tablespoonfuls over casserole. Garnish with fresh cilantro and avocado slices or finely chopped red onion.