Chipotle Pulled Chicken

In a 3-qt. slow cooker, combine the first 14 ingredients; add chicken. Cook, covered, on low 3-4 hours or until chicken is tender (a thermometer should read at least 165°)., Remove chicken from slow cooker. Shred with 2 forks; return to slow cooker. Using tongs, place chicken mixture on bun bottoms and if desired, top with pickle slices. Replace tops.