In medium saucepan, whisk half-and-half, broth, flour, and poultry seasoning until combined. Bring to a boil, reduce heat, and simmer, whisking frequently, 4 minutes, or until thickened. Stir in chicken, mixed vegetables, scallions, salt, and pepper. Cover and keep warm.
Lightly coat 5 (6 oz) ramekins or one pie dish with cooking spray. On a lightly floured surface, overlap 2 biscuits (if using whole dish, use all biscuits) and press edges together; roll biscuits into a 4-inch round (they don't have to be perfect). Roll out remaining biscuits the same way. Fill ramekins with chicken mixture. Top each with biscuit dough, pressing dough onto side of ramekin to adhere; cut a 1/2-inch-round vent hole in middle of dough.
Bake 12 minutes, or until biscuits are golden and filling bubbly. Let stand 5 minutes before serving.