Coat a 3 1/2 to 4 quart crockpot with nonstick cooking spray. Place chicken in cooker, sprinkle with tapioca, salt, and pepper and top with hoisin sauce.
Cover and cook on LOW for 4 to 5 hours.
Turn to HIGH heat setting, stir in vegetables; cover and cook for 30 to 45 minutes more. Serve over hot cooked rice.