The champion trainer will face charges that he was guilty of improper or violent conduct and that he brought racing into disrepute.
Nicholson is alleged to have struck out at Racing Post photographer Edward Whitaker in the aftermath of the King George VI Chase. The trainer was angry that Whitaker was photographing a tearful Adrian Maguire after the jockey's dramatic last-fence fall from the clear leader Barton Bank.
It had appeared that the matter was dead and buried until the Jockey Club's announcement yesterday. But the Club's spokesman David Pipe said: "It's not something that's been suddenly decided. We've been collecting statements and the stewards have now decided to go ahead with an inquiry."
No date has yet been set for the hearing and it may be delayed should Nicholson decide to have legal representation.
When asked if he was surprised that the Jockey Club had decided to hold an inquiry, the trainer responded with a terse: "No comment."
Pipe was unwilling to speculate on the punishment that would be given to Nicholson should he be found to be in breach of the rules. "The stewards have wide-ranging powers and it is entirely up to them what happens," he said.
There have been few recent cases of trainers facing disciplinary action for similar offences. But Jenny Pitman was fined £200 for violent and improper behaviour after an altercation with Jamie Osborne at Ayr in 1990.
nThe Classic contender Moonshell will follow the same route as Balanchine last year and, after wintering in Dubai, will tackle the 1,000 Guineas without the benefit of a prep race. Quoted at 14-1 by William Hill for the first fillies' Classic, she was animpressive winner of her only race, at Doncaster in October. Balanchine is flourishing after suffering a near fatal bout of colic last June and may return to action in the Prince of Wales's Stakes at Royal Ascot.Reuse content