What if the key is no longer with the car? A Nissan service centre doesn't have a way of getting the wheels off without the customer's own wheelnut key?
I've only been 1,500 miles in my Leaf in a year so I'm lacking motivation in getting on top of things like what to do in the event of a puncture. I must get my act together though.You will also need the locking wheel nut key if you have to change the tyres of have to have a puncture fixed.
I keep my one with the tow hook in with the granny charger in the rear wheel arch stowage net, so it could be worth checking the nets both sides.
Failing that, check the secret compartment in the near side rear wheel arch - where the tyre inflator gunk is stowed.