The 24-year-old moved to St James’ Park in a deal worth just under €15 million (£11.8m).
But while Nicollin admits the midfielder has the ability to prosper in the Premier League, he feels the France international should have left Ligue 1 for a more successful club.
"He wanted to go. I wasn't happy, but I told him, 'Congratulations’,” Nicollin told Foot Mercato.
"In England, there is Arsenal, Manchester City, Manchester United, which are above Newcastle, but Newcastle is a club with a lot of French [players]. He likes them, so great.
"Personally, I would not go to Newcastle. But hey, I'll see him when he plays against a club in London.
"He has what he wants, fine, we'll see. But in any case, he has the ability to succeed in England, that's for sure.
"He is frail, but he's hard to catch."