Sprinkle chicken with salt and pepper. Place in slow cooker. Combine ginger, garlic, broth and syrup from pineapple; set aside. Cut pineapple slices into fourths. Arrange pineapple and water chestnuts over chicken. Pour ginger sauce over all. Cover and cook on high 1 hour; reduce heat to low and cook an additional 2 to 3 hours or until chicken is tender (it can be cooked up to 8 hours). Add green onions. Dissolve cornstarch in soy sauce and vinegar. Stir into pot. Cover and cook on high 10 to 15 minutes or until slightly thickened. Serve with crisp Chinese noodles.