Preheat the oven to 350. Prepare a 13 "x 9" pan with cooking spray; set aside. In a mixing bowl, combine turkey, mixed vegetables, chicken broth, and mushroom soup. Mix well. Spoon mixture into prepared pan. In another mixing bowl, combine baking mix, milk, and margarine. Mix until smooth. Pour evenly over top turkey mixture in pan. Bake for one hour, or until topping is golden brown.