One thing to be aware of if thinking of applying for Nexus is that the application will stall renewal of any other rapid entry creditation. For example Global Entry.
I was a Global Entry holder and applied for Nexus. There were no interviews obviously for two years so my Nexus app just sat there. In the meantime my Global Entry was coming up for expiry.
I was unable to renew Global Entry because of the pending Nexus application. This was verified in several lengthy discussions with CBP.
Ultimately in order to renew my Global Entry prior to its expiry I had to withdraw my Nexus application (and forfeit the application fee).
Once I had completed that, the online tool allowed me to renew Global Entry.