Place chicken in a 3-qt. slow cooker. In a small bowl, combine the syrup, mustard and tapioca; pour over chicken. Cover and cook on low for 3-4 hours or until tender. Serve with rice. Freeze option: Cool chicken in sauce. Freeze in freezer containers. To use, partially thaw in refrigerator overnight. Heat through slowly in a covered skillet until a thermometer inserted in chicken reads 165°, stirring occasionally; add broth or water if necessary.