Preheat over to 400°. Remove Puff Pastry from freezer to thaw.
In a small bowl, mix the cubed chicken, Tony's, salt and pepper until the chicken in coated.
In a large saute pan, heat oil over medium heat. Saute chicken until cooked all the way through. set aside in a small bowl.
In the same pan, melt butter over medium heat. Add onions, carrots, celery, garlic, and mushrooms. Saute for 4-5 minutes or until soft. Add Dried thyme and Tarragon. Stir.
Add flour. Stir until combined. Pour in milk and chicken stock. Mix until flour is dissolved.
Add return chicken to the pan. Add water chestnuts, frozen peas, Tony's, Salt, and creole mustard. Bring to a low boil.
Boil for about 3-4 minutes. Reduce heat to low, and let simmer for about 20 minutes. The filling will continue to thicken.
When the puff pastry is thawed and the filling has thickened, Pour filling into a 9 inch pie pan. Cover pie pan with puff pastry.
Bake for 20 minutes. About 5 minutes before it is done, brush pastry with melted butter (if desired).
Removed from oven. Let stand for a few minutes before cutting.
Serve and enjoy!