In a medium sauce pan, over medium high heat, melt the butter.
Once the butter has melted, add in the flour. Whisk until boiling. Whisk and boil for 30 seconds.
Add in the broth and the milk. Whisk until smooth.
Add in the salt and pepper, continue to boil until thick.
In a large bowl combine the chicken, peas & carrots, hash browns, onion and the mixture from the sauce pan. Stir to combine.
Place one of the pie crusts in the bottom of a 9 inch pie plate.
Pour the pot pie filling into the pie plate, spread evenly.
Top with the second pie crust. Seal and pinch the edges. Cover the edges of the pie crust with foil.
Bake at 350° for a total of 1 hour. Bake with the edges covered for the first 30 minutes, remove the foil and bake for an additional 30 minutes.
Remove from the oven when the crust is golden brown. Allow to cool for 5-10 minutes before serving.
Whisk together the gravy packets and cold water over medium high heat to make the gravy. Pour over sliced Chicken Pot Pie if desired.