Place 3 boneless chicken breasts, 1 can (10.5 oz) cream of chicken soup, 1 cup milk, ½ onion chopped, 4 potatoes peeled and diced, 16 oz frozen mixed vegetables, ½ cup chopped celery, 1 teaspoon garlic powder, ½ teaspoon poultry seasoning, 1 teaspoon salt, and ½ teaspoon pepper into the crock pot.
Cover and cook on low for 6–8 hours or on high for 3–4 hours, until the chicken is fully cooked and the potatoes are tender.
Remove the chicken breasts from the crock pot and shred them with two forks.
Return the shredded chicken to the crock pot and stir well to combine with the vegetable mixture.
Bake the 16 oz (8 count) Grands biscuits according to the package directions.
To serve, spoon the chicken pot pie mixture into bowls and top each serving with a baked biscuit. Serve warm.