In a large bowl, combine shredded chicken, diced carrots, peas, corn, and chopped onion.
Pour in the chicken broth and heavy cream.
Season with garlic powder, salt, and pepper.
Stir the mixture until well combined.
Transfer the mixture to the crockpot.
Cover and cook on low for 6-8 hours or high for 3-4 hours.
Preheat your oven to 425°F (220°C) about 30 minutes before serving.
Roll out the pie crust and place it over the crockpot.
Bake in the oven until the crust is golden brown, about 15-20 minutes.
Let cool for a few minutes before serving.