Place all ingredients, except lettuce, in a large slow cooker; give the mixture a good stir.
Cover and cook on LOW for 8 to 10 hours, stirring every few hours. When chicken is very tender, shred it with 2 forks and blend with slow cooker juices.
Fill each lettuce leaf with a portion of the chicken mixture, roll up and enjoy!
Notes
SERVING SUGGESTION: A relish tray of jicama sticks, baby carrots, cherry tomatoes, cucumber spears and radishes.