Originally Posted by
Xyzzy
Starting Feb. 25, 2025, Canadians (and any alien coming to the US) staying l
nger than 30 days have to register with USCIS.
Details here. Regarding NEXUS specifically, that page also states this:
Aliens who have already registered include ... Aliens issued Border Crossing Cards.
As mentioned it calls out fingerprinting as the requirement for registration; most if not all adult Nexus card holders are presumably fingerprinted. I don't believe my children are, but they are still under 14.