Start by making the coleslaw. In a medium bowl, add the shredded red and green cabbage and carrots.
Add the mayo, sugar, apple cider vinegar, and celery seed to a small bowl. Mix until thoroughly combined. Add salt to taste and set aside.
Shred the chicken and heat it through. Set aside.
Toast the brioche buns in a dry skillet.
Start to assemble, add the coleslaw to the bottom of the bun. Top with the shredded chicken and finish with some pickles. Add the top bun and enjoy!