We entered yesterday and this was also our experience, but we're in Gananoque, Ontario. Just had to call the Nexus 866 number to get clearance a minimum of 30 minutes prior to arrival.
The only nuisance was; I spent 40 minutes on hold(!) which meant we were then much closer to the marina. Fortunately the officer on the phone was very nice about it and just said something about staying on the boat a few minutes longer after we docked.
Anyway, I wish they would bring back some kind of app like ArriveCan... having all the critical numbers and addresses punched into an app is more efficient than reciting them over a long phone call...
