The in-form left-hander has been reported by the match umpires for allegedly tampering with the ball during a Plunket Shield match at Hagley Oval earlier this week.
The 31-year-old, who has been named in the Black Caps test squad for their tour of Bangladesh later this month, was captured on the live stream allegedly interfering with the ball at the end of the 32nd, 33rd and 35th over during Auckland’s second innings.
He appears to scrape the ball across the back of a helmet each time.
New Zealand Cricket (NZC) head of cricket operations Charlie Brewer and Auckland Cricket Association chief executive Iain Laxon declined to comment yesterday.
"Rule 3.1, article 1.15 involves changing the condition of the ball in breach of law 41.3 of the laws of cricket.
"As a level 2 matter, the allegation will be referred to, and heard by an NZC first-class commissioner."
That process is expected to take place as quickly as possible and Nicholls, if found guilty, is looking at the loss of part, or all, of his match fee, "and/or suspension for a number of matches" according the code of conduct.
If suspended his spot on the tour would surely be untenable.
There have been many incidents of ball-tampering in the international game, the most notable being "sandpaper-gate" when Australian Cameron Bancroft used a piece of sandpaper to alter the surface of the ball during the third test against South Africa in 2018.
He was banned from cricket for nine months, while vice-captain David Warner and captain Steve Smith were banned for 12 months.
A well-informed source told the Otago Daily Times the Auckland players had been aware Nicholls may have been using the helmet to scuff the ball up in order to help it reverse swing and had filmed him from the sideline.
Canterbury was in a dominant position in the game and went on to win by eight wickets. But Auckland had rallied and was 72 for none at the time of the first alleged incident.
They were eventually bundled out for 256. Wrist spinner Michael Rippon took four for 85.
Nicholls, who has scored 2948 runs for New Zealand in 54 tests, played a starring role in the game. His first-innings knock of 120 laid the platform for the victory.
And late last month he scored 124 and 61 against Otago.
