Nikora has been the pursuit of a race between clubs for his services, with it believed that the Wests Tigers have been most heavily chasing him outside of the Sharks.
The Sharks have previously stated they wouldn't get into a bidding war for the New Zealander, but have reportedly won the race for his services.
Alongside the Tigers, the Parramatta Eels - who have lost Isaiah Papali'i and Marata Niukore from their back row, but could also yet lose Ryan Matterson, also made inquiries, while reports earlier in the piece suggested the New Zealand Warriors may also have been keen.
The Sydney Morning Herald's Adrian Proszenko told SEN Radio that the deal was a three-year one.
"Briton Nikora. Incorrect," Proszenko said when quizzed over whether he had signed for the Warriors.
"He has just been named as part of Michael Maguire's New Zealand squad, but he will be staying put.
"A little bit of breaking news, but they are very close to sorting something out with the Sharks. He wants to stay, likely for three years.
"There was interest from other clubs. The Tigers were quite keen and Parramatta had a little sniff as well. The deal isn't done, but it's very close.
"They (the Sharks) are working through a number of guys off-contract. Jesse Colquhorn has just been done, Todd Hazleton will be done, they will want to have a look at Wade Graham and Andrew Fifita over the next four to six weeks, and there is a question mark over Tolman.
"But certainly Nikora, he will stay."
Nikora has played 74 NRL games, scoring 17 tries and barely missing a game since his debut year in 2019 saw him play all 24 contests for Cronulla.