Also worth noting that like Canadian citizens and legal permanent residents are guaranteed entry to Canada the same does I believe hold for a US citizen at least.

If you can get to the border, they can’t legally deny you entry. Depending upon time of day, mood of agent and what you have on you this might take 2 minutes or hours/days.

And of course there is no way your getting on a plane without a passport or Nexus. The chance of getting on a plane with only Nexus seems up for debate.

As an aside, I require my passport and PR to get on a plane to Canada. But I’ve never had to show my passport once I get TO Canada Machines and agents alike are happy with the PR card.

Hopefully OP can report back once they are allowed to.