In a slow cooker, combine chicken, onions, celery stalk, garlic, and broth (enough to cover your chicken, use water if the can of broth is not enough).
Cover and cook on high 4 hours.
Remove the chicken from the pot, reserve 1/2 cup broth and discard the rest.
Shred the chicken with two forks, return to the slow cooker with the 1/2 cup broth and the hot sauce and set on high for an additional 30 minutes. Makes 3 cups chicken.
To prepare lettuce cups, place 1/2 cup buffalo chicken in each leaf, top with 1/4 cup shredded carrots, celery, and dressing of your choice. Wrap up and start eating!