In a small skillet, heat one tablespoon of butter and add the seasoned white meat chicken chunks. Personally I prefer the classic salt, pepper, garlic and onion powder (but you can cater to your liking). After the chicken is cooked, set it aside.
Add onion and frozen vegetables to a stock pot with 1/4 cup of water and add 2 tablespoons of butter. Let the veggies cook while stirring constantly for about 5 minutes over med-high heat.
After veggies are fork-tender, add your flour to the mixture, and coat all veggies. Then, whisk in the warmed milk, and broth to create a roux. To warm your milk and broth, simply pop them in the microwave in microwave-safe containers for 90 seconds. This allows them to mix in with the flour easier.
Add chicken to the pot, and additional black pepper; stir until thick and uniformly creamy over high heat. This will take about 20 minutes to thicken and cook off some of the liquid.
Heat oven to 425°F. and line a large pie plate with one pie crust-prick holes in the bottom using a fork; set aside.
Once mixture is ready, add it to the pie, and then cover the top of the pie, and crimp edges. Be sure to add holes, and slits to allow the pie to vent.
Bake for 35 minutes or until the pie is a golden brown color.
Allow pie to rest for 15 minutes before slicing.