Originally Posted by
colonius
If you do your Nexus interview at a station without an iris scanner, which includes most (all?) locations in the USA, you will need to add your iris scan at a suitable location later on (most locations do this without an appointment). Until then, the Nexus Air function will not work.
The iris scanning stations are only located in Canada; there are none in the US. Note that the iris requirement is for immigration activities that occur in Canadian airports (including entry to Canada and US pre-clearance upon exit).
To use NEXUS in the Canadian airports, an applicant must travel to an enrollment center to have their iris captured giving him or her access to the airport kiosks to report their arrival into the US or Canada. To have your iris captured, you can travel to the Canadian airports in Vancouver, Toronto, Montreal, Ottawa, Calgary, Edmonton, Winnipeg, Halifax, or the Fort Erie, Canada Enrollment Center.