Spray slow cooker with cooking spray.
Place chicken into crockpot
Cover with onions, carrots, celery and sweet potato
In a medium bowl whisk together chicken soup, milk, garlic, salt, celery salt, and black pepper.
Pour soup mixture over chicken and veggies, stir to coat.
Cook on low for 5.5 hours.
Stir the frozen mixed vegetables into the slow cooker, and cook 1 hour more.
Serve topped with biscuit
