Preheat oven to 450 degrees.
In a deep, 8-inch skillet, heat the olive oil over medium heat. Season the chicken with salt and pepper and add to the skillet cooking until done and no longer pink. Transfer to a plate and allow to rest until cool enough to handle. Cut the chicken into bite sized pieces.
Add the carrots, onion and celery to the skillet and sauté until softened. Add the garlic and peas continuing to cook for approximately 1 minute. Stir in the garlic powder, nutmeg, thyme and chicken stock and bring to a boil.
In a small bowl, whisk together the cornstarch and half and half. Add the mixture to the skillet and turn the heat to low. Allow to cook until thickened and then stir in the chicken. Top the filling with the pie crust and press down along the edges to seal. Using a knife, cut two 1-inch slits in the middle of the crust and transfer to the oven.
Bake the pot pie for 15-20 minutes or until the crust is golden brown. Remove and serve immediately.