Thousands of fans gathered on Montpellier's Place de la Comedie in light rain to cheer the team, who paraded on a double-decker bus painted in the team's colours of orange and blue.
Nicollin, a 68-year-old businessman and one of the most colourful characters in French football, also had his hair dyed in the same colours.
As Montpellier, a family-run club still in Ligue 2 three years ago, savoured their success, the inquest continued into the crowd trouble that marred their final game of the season on Sunday.
Montpellier won 2-1 away at relegated AJ Auxerre in a game that was interrupted three times as home fans threw tennis balls, tomatoes and then flares onto the pitch.
"We are going to watch the footage and look for the troublemakers," the prefect of the Yonne department, Jean-Paul Bonnetain, told Reuters by telephone on Monday.
"The question is how so many flares made their way into the stadium? There will be sanctions and I will follow a hard line. There could be six-month stadium bans."
The game was interrupted for a total of 41 minutes, with anti-riot police called in by Bonnetain to deal with the troublemakers.
"It takes time to clear a 2,000 stand. There are about 300 or 400 diehards, but also women and children," Bonnetain explained.
The French League said it would look into the matter when the disciplinary committee convenes on Thursday, with Auxerre possibly facing multiple matches behind closed doors in Ligue 2 next season.