Yes. As long as there's at least one US citizen or permanent resident on your team, and you're not a specially designated national, you're allowed to participate.
So ya, Canadians are allowed but only if the boss is a US citizen. Don't see any resident language. I make the point because some of the best satellite spotters/finders/hackers are Canadians, such Scott Tilley who was recently in the news for finding a long-forgotten navigation sat. Or Ted Molczan who may have spotted the legendary Prowler sat.
(This is natural. Canadians are better positioned to spot satellites due to their darker sky and the longer dawn/dusk periods of higher latitudes.)
official technical point of contact for communications != boss