Jenny McGee, along with Luis Pitarma from Portugal, was praised by the PM for standing at his bedside "when things could have gone either way".
Ms McGee's parents told Television New Zealand they are "exceptionally proud".
They said she treated Mr Johnson like any other patient.
Mr Johnson was discharged from St Thomas' Hospital in London on Sunday, one week after being admitted to be treated for coronavirus. He spent several nights in the intensive care unit where he was given oxygen.