Assuming you are referring to departing from a Canadian airport, your physical NEXUS card is required to use their version of PreCheck.

Perhaps you have prescription glasses, you can wear it to have your iris scanned without an appointment. You can also wear it when entering a Canadian airport.

NEXUS card will allow you to access CATSA Trusted Traveller security line; it won't allow you to bypass security. ;)

Just to be clear, you can visit a Nexus enrollment center to get an iris scan. All airport locations take iris photographs, and some non-airport locations do as well. No appointment is needed in order to just get an iris scan - in fact it is not possible to make an appointment for just an iris scan, that service is walk-in only.

Canada Border Services Agency - NEXUS Enrolment Centres

I had a while where the nexus machines wouldn't register my iris for whatever reason. So I would typically take the Nexus lane anyways and just tell CATSA of the issue. They would make me fill out a CBSA declaration card on the spot, but yes, one would skip the long line ups from normal immigration.

You only have to show your nexus card to get into the special CATSA security line - they don't make you scan your irises. That's only for CBSA when arriving into Canada.

GETTING CONFLICTING INFORMATION: Today at a Nexus renewal appointment at a Canadian Airport I was told by the CBSA agent that it is not enough to update passport information in the Trusted Traveler Program System. I was told that any time personal documentation changed that I must also physically report to the NEXUS office to have the information updated. i was also told that just becauseI had updated the information in the TPP system it does not get relayed to the Canada. This information which I received in person seems contradictory to that information which is on the CBSA site

NEXUS members can access the Trusted Traveler Programs (TTP) System to update a mailing address change and passport information that is already on file.

Please note that NEXUS members are not required to report to an Enrolment Centre to update or change their passport information with the CBSA.

NEXUS members must report to an Enrolment Centre to update or change other information including:

Legal name changes
Changes to citizenship documents
Changes to permanent resident card information
Changes to naturalization certificates
Changes to work visas or study permit information
Changes to employment information if the change affects your eligibility to the program
Change to residential address only if the change affects your eligibility to the program
Changes to legal custody and legal guardian status or jurisdiction (for all NEXUS members under 18)
Changes that could affect your NEXUS membership such as an arrest, a criminal charge, a conviction or a customs or immigration violation in Canada or the United States
Purpose of travel changes (business/pleasure/school, etc)
To update an email address, please contact a Canadian Processing Centre.

Per prior posts here, apparently the web site documented procedures are correct and the CBSA agent statement is not correct. Apparently the reason the CBSA agents at interview offices have the impression that TTP updates are insufficient is that "they" don't see them. Apparently the system is designed so that staff that need the information (such as customs inspectors at the airports) see all information, but renewal office agents don't see all updates (why would they have any need to see them anyway, unless they were going to interview that individual?). It actually makes sense - provide private information only to the staff that need it.

It is indeed contradictory. However from experience, the agent is correct. When you update the information online, it does not actually get updated with CBSA. I moved across Canada over a year ago, and I had updated it online at that time. Only until 3 months ago when I was there to update my visa information that I was asked if I still lived at my previous address...and was told that updating online does nothing.

I was told the account was flagged because the Canadian side didn't have updated passport information. I did update information on TTP site as soon as new passport was received (about year 3 into Nexus period). I was very specifically told, today, that the information in TTP is not given to the Canadian side and that not bringing the passport in to a Canadian Nexus processing center was a violation of the Nexus rules. The renewal was not going to be denied today but in future I must ensure that I update information both on the TTP site and in person at a Canadian processing center. The agent was very nice when conveying this information to me.

Just to clarify that the CBSA NEXUS enrollment centre not seeing the online update sounds to be accurate but inconsequential as far as using NEXUS to enter Canada or US is concern. What matters is the system CBSA port of entry is using do have the online updates.

Recent data points confirm this.
https://www.flyertalk.com/forum/30520508-post11132.html
https://www.flyertalk.com/forum/showpost.php?p=30466374&postcount=11122

ConfusedNexusUser - I presume you filled out a renewal application. If so, it would have went thru background check processes by both CBSA Immigration Processing Centre and CBP and conditionally approved before allow you are allowed to interview. So if the enrollment centre is seeing your old passport from 2 years ago (assuming 5 year expiration and you indicated you updated online 3rd year since prior interview), that is indication that they really don't get updates but the CBSA processing centre did in order to do the background check and eligibility verification.

Meh, they have gotten a lot better about this since the countless threads about various ordeals - including multiple of mine - from 7-8 years ago. I've not had NEXUS challenged at any airport, including places like Montgomery, AL, in at least 5 years.

We somehow let my wife's Nexus pass expire last year (she didn't leave the country that year) and discovered this until the day before we started our trip. FWIW, KTN entered into WS reservation after expiration yielded Pre-Check (FWIW, departing Canada?) on the second leg. Used the passes to avoid the long line for transit security and it managed to get us into the immigration fast lane too for pre-clearance (we used the normal machines).

Departing the U.S. tomorrow with a flight that participates in Pre-Check, and will have flights arriving into and leaving the U.S. in a couple of months where KTN is inputable.

Any idea how long applications are taking nowadays? I applied for renewal for my wife's and mine, and a new application for our newborn, back in January. My wife's was approved right away, but mine and the baby's are still pending review.

TIA

They can still use the machine. When we took our toddler through, the fingerprint scan part was just blanked out. The ticket that printed forced us to go to a booth and see an agent, but there was no hassle there, just a couple quick questions and some keystrokes. He got his Nexus card when he was only a few weeks old, so even if they took fingerprints back then, they probably wouldn't match now that he's almost 3.

Please check out the following threads: