Applied in May 2022 and still waiting. I called both the CBP and CBSA NEXUS lines. The CBP line was extremely confrontational and was rude from the offset. I asked them if they had any additional information from me, they called me a liar, and hung up on me when I said FOIA. Later, I called the CBSA line and they told me I had passed the Canadian background check in June 2022 and my application was only waiting for the US side to pass.

I already have Global Entry and that only took 4 months to process, so I couldn't possibly imagine why it would now take over a year for the CBP to do my background check.

Lesson learned: don't bother calling CBP, just call the CBSA NEXUS line.