Flying in and out of U.S with just Nexus

I am in YYZ, on my way to SFO. Silly me left my passport at home and I was able to check in, clear security with just Nexus.

I am wondering if I will have issues flying back home from SFO later this week.

What has been your experience been like? I've done this once between YYZ and Logan BOS but this was eons ago pre-pandemic.