frying in oil will seal the chicken on the outside but will evaporate a lot more moisture than poaching, which will release the fats and should as it is in water, stay more moist,
the more water and fats that are lost in the cooking will make the meat dry and tougherless tender,
i think they probably cut the meat and poach it/blanch it quite a bit, then stir fry for the minimal amount of time to bring it to a fully cooked state..
tired and hammered, so this might not make much sense sorry!