I know that Panago has been offering Daiya cheese on Pizza since 2015 but I don't know of any other pizza chain restaurants offering dairy-free cheese in Canada. Is Panago the only one?
Pizza Pizza rolled out vegan cheese across all Canadian chain restaurants this past year (at no extra cost!)
Here is an article by PETA on Pizza Pizza adding vegan cheese to their menu.
Pizza Nova seems to have incorporated dairy free cheese at select locations starting as early as 2014 according to this press release on their website. However, this may only be available to those in Toronto and Southern Ontario. Additionally, both their standard dough and the gluten free dough are vegan. The two kinds of tomato sauce are also vegan. Pizza Nova has Daiya cheese available at no extra charge, according to this.