Heat oven to 425.
In a saucepan, melt butter and add onions, cook for about 1 min.
Stir in flour, salt, pepper, and blend well.
Stir in broth and milk, cook and stir until thick and bubbly.
Stir in chicken and vegetables, remove from heat.
Spoon mixture into pie crust.
Cover with other crust and seal the edges of the crust by pressing them together.
Cut slits in 4 places in the crust.
Bake 30-40 mins. until crust is brown.