Nicholson took the record as Badminton's eldest champion from Sir Mark Todd who was 55 years, one month and 24 days old when he completed his fourth victory, on NZB Land Vision, in 2011.
Todd's effort saw him selected as a Halberg Award sportsman of the year finalist; Nicholson last featured in that category in 2012 and 2013.
The unbridled passion accompanying Nicholson's 37th - but first victorious - Badminton completion was understandable. No one has completed more, and he rebuilt his body, mind and career to do so.
"The feeling is unbelievable," Nicholson said at the time. "I've been waiting so long for it. When I was young it seemed quite easy to win Badminton; just be brave and away you go. I found out it's very difficult."
Nicholson's words hold weight. His previous journey, in 2015, to the Duke of Beaufort's estate in Gloucestershire saw him and Nereo enter the showjumping as overnight leaders. Three dropped rails later they had finished sixth.
Nicholson staked everything on his horsemanship after suffering a broken neck at the Festival of British Eventing at Gatcombe Park later that year on August 9.
A shattered vertebrae was the difference between maintaining his vocation or tetraplegia. Similar accidents to the cervical spine paralyse 98 per cent of sufferers and destroy the lives of others when the delicate but mandatory surgical procedure goes awry.
Nicholson was saved because the vertebrae's explosion released the pressure on his spinal cord. He got up, walked around and didn't exhibit the usual devastating symptoms.
In short, Nicholson's recovery has been miraculous.
The patrons at Badminton knew that as they rose to bestow a standing ovation when he and Nereo's owner Libby Sellar received the winner's trophy.
Victory at four-star events are considered the equivalent or better of an Olympic gold medal in the equestrian community. Nicholson has nine such crowns: Burghley (five times), Kentucky, Pau and Luhmuhlen and now Badminton.
Hopefully the Halberg Awards organisers also realise the extent of Nicholson's accomplishment before the finalists are released next month.
Sportsman of the Year nominations (as listed on the halbergawards.co.nz website)
Aaron Gate (cycling), Aiken Hakes (croquet), Beauden Barrett (rugby), Brendon Hartley (motorsport), Chris Wood (football), Ethan Mitchell (cycling), George Bennett (cycling), Jason Wynyard (wood-chopping), Joel Henare (shearing sports), John Kirkpatrick (shearing sports), Kane Williamson (cricket), Michael Venus (tennis), Peter Michael (ice speed skating), Robbie Manson (rowing), Sam Gaze (cycling), Tom Walsh (athletics).