Add the chicken breasts to a 4 qt slow cooker.
Season with garlic powder, onion powder, and pepper.
Place the butter on top of the chicken and pour the buffalo sauce over top.
Cover and cook on low for 4 to 5 hours or on high for 2 to 3 hours or until the chicken reaches an internal temperature of 165°F and is very tender.
Shred the chicken in the slow cooker with 2 forks or by using a hand mixer.
Serve on brioche buns with coleslaw mix.
