Wash your hands well with soap and warm water for at least 20 seconds.
Remove pie crust from refrigerator and let stand at room temperature for 15 to 20 minutes.
Mix chicken, vegetables, cream of chicken soup, and sour cream in a medium mixing bowl. If using canned chicken, drain before adding to the bowl.
Coat 8- to 9-inch square or round baking dish with vegetable oil cooking spray and add mixture. Place pie crust over the mixture, overlapping the edges of the dish and pressing the crust around the sides to seal. Make several small slits in top to allow steam to escape. Bake for 1 hour.