Preheat oven to 425°F and prepare pie crusts as directed on box using a 9-inch pie pan.

In a sauté pan, melt butter over medium heat. Add onion and celery, stirring frequently until tender. Mix in flour, salt, and pepper until thoroughly combined.

Stirring constantly, gradually add milk and broth. Bring to a boil and remove from heat. Stir in cooked chicken and vegetables.

Carefully spoon pie filling into crust-lined pie pan. Top with second pie crust, seal edge, and flute.

Cut slits in top crust and bake for 35 minutes or until crust is golden brown. Let pie stand for five minutes.

Serve and enjoy!