Yes, this is an old thread. We're in the same situation - my partner has a NEXUS card based on US citizenship, and we're expecting a brand new Canadian passport any day now. We believe that we should go to an enrollment center to have the new citizenship and passport added to the NEXUS profile.
We've contacted two (US) enrollment centers at land borders. One is convenient for us and is actually open on Saturdays, but when we spoke with them, the CBP officer said as far as the US is concerned, there's no need to do anything, and they don't have access to the systems to do it anyway. Another enrollment center, which is somewhat less convenient, also reported that there's no need to do it, but at least they know what to do (provided their systems aren't down when we show up !). Going there would mean taking time off work, and 1.5 hours driving each way - and then they might not be able to help.
We called the CBSA NEXUS help line for our region (we're in NB) and got an automated message that all enrollment centers are closed for the pandemic. This is clearly untrue - there are two at land crossings, and one at Halifax airport. We tried calling the number for Ontario, and got a human who had never heard of the "walk-in" process, and doubted that it was possible. He suggested waiting for the card to expire and adding the new citizenship then. He didn't think that it mattered to CBSA.
And, just to complete the story, email queries to both CBP and CBSA have gone un-answered after 2 months (both generated auto-responses that suggested that we *might* get a response)
This is all fairly academic for us now. We once used NEXUS a lot when we lived on opposite sides of the Niagara frontier, but it's not much use here, as the NEXUS lanes are only open for local commuters with very limited hours. It's still very useful when we're back in ON or NY for holidays. So we want to do the right thing when we're able.
Does anybody have any evidence to contradict the "we don't care" attitude that we got from both CBP and CBSA ? Can we just continue to use the card until we happen to be someplace where we can do the walk-in ?
I had a different experience contacting CBP through the web form. Here is their response and it appears that they ask me to update the Canadian citizenship change:
Updates to your visa(s), citizenship or immigration status, date of birth, gender, or legal name, and the addition of new documents (such as a second passport or new visa) can be completed by our office. Please read the information below carefully and reply to this message with the information requested below.
NAME CHANGE: Please reply to this message with a color image of your passport reflecting the name change.
CITIZENSHIP OR IMMIGRATION STATUS CHANGE (U.S. citizenship, U.S. LPR status, and Canadian LPR who became a Canadian citizen OR relinquishment of citizenship or residency status): Please reply to this message with images of your new passport, permanent resident card, or relinquishment document.
DRIVER'S LICENSE UPDATE (FAST only): Please reply to this message with an image of your new driver's license.
Address information, phone number, and employment information do not need to be updated until you renew your membership. If you have submitted an application already, you will need to wait until your interview to make any changes.
You can update documents already associated with your account by logging into your TTP Dashboard
https://ttp.dhs.gov/ and clicking on "Update Documents" on the right side of the page. Please note that you will not have this option if you have a pending application.
Driver's License information (renewal only, NOT name or state changes)
Legal Permanent Resident Card (LPR)
Vehicle Information (not VIN number)
Passport (renewal passports only, not name changes or new passport types)
Changes are automatic and no further action is required.
If you need further assistance, please reply to this email and we will investigate how we may further assist you.
Thank you again for contacting the Traveler Communications Center.
