Begin by dicing your fresh onion and celery. In a large mixing bowl, combine the stuffing mix with chicken broth and cream of chicken soup, stirring well until the mixture is evenly moistened.

Place the boneless, skinless chicken breasts at the bottom of the crockpot. Evenly distribute the prepared stuffing mixture over the chicken.

Cover your crockpot with the lid and set it to cook on low for 6-8 hours, or on high for 3-4 hours. Check for doneness; the chicken should be tender and fully cooked.

If the stuffing is too moist, remove the lid and let it cook uncovered for the last 15-30 minutes.

Once cooked, scoop the chicken and stuffing onto plates and serve with gravy or steamed vegetables.