Now playing for Munster in Ireland, Nankivell told balls.ie that his father was adopted and didn't know his parents. However, he had been told that he was Māori.
That led to a quest for more information.
He said, "There was lots of digging and it was pretty special. We ended up finding my dad's birth father.
"He knew his birth mother, we found her a few years ago, but then we found his birth father and all his family.
"It was pretty cool. I got to represent the Māori All Blacks, my family and extended family, and where I'm from."
Nankivell first played for the Māori All Blacks in 2019 and represented them against Ireland last year.
Having signed a two-year contract with Munster after the end of the season in New Zealand, Nankivell joined the side and made his debut against the Sharks last month. His transition was helped by Ireland international John Ryan, who played for the Chiefs this year.
"I had a bit of anxiety coming over, not really knowing too many people, but John Ryan helped me a lot. He was the bridge between coming from the Chiefs to here. It's been awesome. The lads have looked after me."
Gisborne-born Nankivell grew up in Christchurch and is another product of the Christchurch Boys' High School system.
"I've been a rugby nut since I was a kid. I played rugby since I was five years old. I grew up in Christchurch and was then fortunate to get a professional contract out of school.
"I went to the Tasman Mako as an 18-year-old and after a couple of seasons there I got a Super Rugby contract with the Chiefs."
He played 81 games for Tasman between 2015-23 and made 70 appearances for the Chiefs between 2017-23. He played five games for the Māori All Blacks and four times for the All Blacks XV.
"The calibre of players we had at the Chiefs was pretty insance. To play with guys like Sam Cane, Damian McKenzie, it was awesome as a young guy coming into the group.
"We did pretty well the last few years. It's a shame we couldn't get the final in the final this season."
