If I attend and pass my Nexus interview at Blaine, WA, can I then cross the border into Canada using Nexus? I'm asking because if I'm driving 2-3 hours to the border it would be nice to make a Canada weekend out of it.
Usually the card is send weeks after the interview, this site mentions it being 6 to 8 weeks later.
But nothing stops you using your passport (book or card) to cross into Canada after or even before the interview.
In the case you want to fly, you can use the 'card' before holding the actual card, from the moment you have been approved for it, but this does not work for surface travel.
When you get your card you need to activate it online before you use it to cross a border.