Preheat the oven to 375°F (190°C) and lightly grease your baking dish. Pat chicken breasts dry so the sauce sticks better. Arrange them in a single layer for even cooking.
Combine Caesar dressing, sour cream, Parmesan, garlic powder, salt, and pepper in a bowl. Whisk until smooth and creamy. This sauce delivers all the rich flavor in the dish.
Place chicken in the dish and pour sauce evenly over each piece. Cover with foil and bake until chicken reaches an internal temperature of 165°F. Remove foil for the final minutes if you want light browning.
Let the chicken rest briefly after baking so juices settle. Sprinkle chopped parsley over the top and serve with lemon wedges for brightness.