In a 3- or 4-qt. slow cooker, combine first five ingredients. Cook, covered, on low until chicken is tender, 3-4 hours. Remove chicken from slow cooker. Cool slightly; shred chicken with two forks. Return meat to slow cooker. Add corn and rice; cook, covered, on low 1 hour longer. , If desired, serve with cheese, sour cream, avocado and olives.