PLACE chicken in slow cooker; top with artichokes. Whisk next 6 ingredients until blended; pour over artichokes. Cover with lid.
COOK on LOW 6 to 8 hours (or on HIGH 3 to 4 hours). About 1 hour before chicken is ready to serve, cook rice as directed on package, omitting salt.
ADD spinach to ingredients in slow cooker just before serving; mix well. Serve rice topped with chicken mixture and croutons.