I got the instruction from CBSA officer about replacing my card with corrected nationality on the card. However, I contacted CBP TTP couple weeks ago and received the reply from them about updating my Canadian as main nationality. They said as long as the information on the dashboard is correct, I don't necessarily need to apply for a new card.Hi, just wanted to share how the update of citizenship works for the Nexus card. My Nexus was previously connected to my Canadian PR card and my other passport. Going online, it did not look like I was able to add another citizenship, so I went to Pearson airport and did a walk-in on a Saturday afternoon. Waiting time was very reasonable. The officer took copies of my passport and explained that they leave a stash of those in an box. Every couple of days, an officer from the US side comes and takes them, and updates the respective profiles. I am not sure how fast it was done, but when I checked my online profile about a week later, my Canadian passport had already been added. As he had instructed me, I clicked the button to "order replacement card" and as a reason, ticked "change of citizenship". The fee was 25$. I can see online that the request was approved but I now have to wait for the physical card to arrive. My current card references my other citizenship and I can no longer use this as I would use my Canadian passport to enter Canada or the US on any future trip. I am going to the US in about a month, and will then use Mobile Passport Control assuming that my NEXUS card likely will not have arrived so quickly.
If the card is not arrived on time before your trip to USA, just come up with any CBP officers along with your MPC to inquire them about that.