Preheat oven to 375 degrees F and spray a 9-inch pie plate with cooking spray.
For the crust: In a large bowl, mix together the almond flour, 6 tablespoons of softened butter, egg, and salt. Stir in the shredded cheddar cheese.
Divide dough in half and roll each half between two pieces of parchment paper into a circle. Chill for 5-10 minutes.
Place one sheet of dough into the pie plate and bake for 6-8 minutes. Remove from oven.
While the crust bakes, melt 2 tablespoons of butter over medium heat. Sauté celery and onion for 5 minutes until softened. Add chicken broth, cream cheese, and heavy cream, whisking until smooth. Stir in garlic powder, poultry seasoning, celery seed, salt, and pepper.
Reduce heat to low, sprinkle in xanthan gum, and whisk quickly until the mixture thickens to your desired consistency.
Stir in shredded chicken and frozen peas and carrots.
Pour the filling into the bottom pie crust, top with the remaining crust, and press the edges together.