Stan Grossfeld / Globe Staff

Chris "Knuckles" Nilan spoke to students at Lakeshore Catholic High School in Ontario. The former NHL enforcer now speaks against bullying.

Stan Grossfeld / Globe Staff

Nilan, who grew up in West Roxbury, played 13 years in the NHL for the Canadiens, Rangers, and Bruins.

Stan Grossfeld / Globe Staff

Nilan suffered from substance abuse, but now says he is "clean and sober."

Stan Grossfeld / Globe Staff

The former NHL enforcer is now the subject of "The Last Gladiators," a documentary by Academy Award-winning director Alex Gibney.

Stan Grossfeld / Globe Staff

Nilan won a Stanley Cup for the 1986 Montreal Canadiens.

Stan Grossfeld / Globe Staff

At Saint Michael Catholic High School in Ontario, Nilan spoke as part of his "No More Bullies" tour.