My report is from 2 weeks ago at T1 (weekend of Aug 13). The Nexus lanes are indeed closed, there is a separate lane for Nexus cardholders though, so there is some filtering. FYI, if you are pressed for time, like I was, go up to one of those line attendants. She was able to help me skip the line up to drop off the affidavit and Covid test. The US customs wait was 15 minutes (I hold Nexus/GE), however, I noticed that CBP seems to be spending more time on average screening individuals - I would say people were in front of the CBP officer an average of 3 minutes.

Pack your patience, its frustrating since like others said, MLL is closed so you won't really get time to relax.