In a medium sized pot, add chicken stock and bring to a boil
Add both chicken breasts and cook for 10 minutes or until completely cooked
While chicken is cooking, shred cabbage and carrots into a mixing bowl
In a smaller bowl, mix the mayo, red wine vinegar, sugar, celery salt, and pepper
Toss cabbage mixture with dressing and let sit in the refrigerator for at least 10 minutes
After chicken is cooked and slightly cooled, shred with 2 forks and place in a separate bowl
At this point you can either add your favorite bbq sauce or continue on to make your own
For the barbecue sauce, add ketchup, apple cider vinegar and remaining ingredients in a small pot and simmer over medium - low heat
Toss the barbecue sauce with the shredded chicken and serve on freshly toasted brioche buns with the coleslaw topping. Enjoy!