Cut chicken into strips about 1 1/2 inches long and 1/4 inch wide. Place in slow cooker with celery, green onions, salt and gingerroot. In a small bowl combine broth, soy sauce and sugar, pour mixture over chicken. Cover and cook on LOW 5 to 6 hours.
Turn control to HIGH. Add mushrooms and bean sprouts. Cover and cook about 5 minutes. Drizzle sesame oil over mixture, stir to mix. Dissolve cornstarch in water and stir into chicken mixture. Cover and cook on High 10 to 15 minutes.
Serve with cooked rice.