Heat oven to 375. Heat chicken, 1/2 cup milk, the sour cream and the soup to boiling. Spoon into rectangular baking dish, 13x9x2 inches.
Beat remaining ingredients except chhese with a wire whisk about 1 minute or until almost smooth. Pour evenly over hot chicken mixture. Spinkle with Cheese.
Bake uncovered 20 to 25 minutes or until top is set and soup mixture bubbles around edge.