The PR Guru - who now hosts Channel 4's Countdown - was an aide to Lord Sugar on the BBC One series for a decade.
But chatting recently about his time on the show, Nick revealed it was a "nightmare".
“People say ‘Oh, it must be such fun to work on the Apprentice!’" he said. “Everybody says that: ‘What fun that must be’.
“Well I’ve got to tell you, for the elderly, it’s one of the biggest nightmares I’ve ever had to endure."
Nick explained to The Sun newspaper: "Can you imagine, even at your young age, having to spend two or three days chasing around after maybe six or eight hooligans?
“It was ghastly! And eventually, after ten years, I said ‘That’s enough’, so I left.”
Nick stepped down from the show in 2014, replaced for the 2015 series by Claude Littner.
The Apprentice 2016 continues Thursday nights on BBC One.