In A Bowl, Combine The Sour Cream, Soup And Poppy Seeds. Stir In Chicken. Pour Into A Greased 11-In. X 7-In. X 2-In. Baking Dish. Combine The Cracker Crumbs And Butter; Sprinkle Over Top. Bake, Uncovered, At 350 Degrees F For 25-30 Minutes Or Until Heated Through.