In a saucepan, add the carrots and potato. Fill with enough water to cover the vegetables. Bring to a boil until tender.
Meanwhile, in a skillet, melt the butter over medium heat. Add the celery, onion and garlic and cook under tender, stirring occasionally.
Drain the water from the potatoes. Add the celery mixture in with the potatoes. Stir in the and combine with the celery mixture. Stir in the chicken soup and water. Stir in the chicken and bring to a simmer a few minutes or until the mixture is hot.
Spoon the mixture into the crust and top with crust. Bake at 350 degrees F for 20 – 30 minutes or until crust browns and sets.