In large sauce pan, saute onion in oil until tender. Stir in flour and poultry seasoning until blended; gradually add broth and milk. Bring to a boil; cook and stir for 2 minutes or until thickened. Add chicken and vegetables.

Tranfer to a greased 9 in deep dish pie plate. Top with pastry. Trim, seal and flute edges. Cut slits in pastry. Bake at 450° for 15-20 minutes or until crust is golden brown and filling is bubbly.