Nexus is a requirement for Canadians to get an APEC business travel card:
https://www.cbsa-asfc.gc.ca/prog/abt.../menu-eng.html
But you still have to apply for it, you can't use your Nexus card.
You don't get visa-free travel, but get to use their special lanes.
This is not first-hand information, just something I found while doing similar research.