Biggest change if you haven't been through in a while is the kiosks used to enter the US have shifted to using facial recognition. All you do is stand in front of it and it takes a photo of you - may have to hit the start button, but other than that no answering questions, no inserting the card or passport, etc
The Canadian kiosks, in constrast, will require you to scan your Nexus card, and if its the first time you've used them since they upgraded from iris scans, you'll have to scan your passport as well so have both accessible.