Heat oven to 375°F. Spray 8-inch square (2-quart) glass baking dish with cooking spray. In 2-quart saucepan, mix soup, milk and vegetables. Heat to boiling over medium heat, stirring occasionally to prevent sticking.
Stir in turkey, sour cream and poultry seasoning. Cook and stir just until thoroughly heated. Spoon into baking dish. Arrange frozen biscuits over hot mixture.
Bake uncovered 30 to 35 minutes or until biscuits are golden brown.