Add chicken to the crock of a six quart slow cooker.
Add Ty Ling Hoisin sauce, chili sauce, soy sauce, ginger and garlic to slow cooker insert.
Cook on LOW for 4 hours.
Remove chicken to cutting board to shred and return to slow cooker. Cook on HIGH for 30 minutes uncovered to reduce liquid.
Meanwhile, in a large bowl, add Napa cabbage, red cabbage, carrots, vinegar and sugar.
Toss slaw ingredients together to combine.
To serve tacos, warm tortillas and layer with cabbage slaw and chicken. Garnish with fresh cilantro, if desired.