I think Nissan's idea on that issue is, the 120V emergency EVSE cord is supposed to stay with the Leaf, at all times. In other words , coil it up and throw it in the trunk, problem solved.
Equivalent charging cables will also be available from many non-Nissan sources, almost certainly at a lower price. There is nothing Leaf-specific about this; it's just a standard 120v J1772 EVSE, interchangeable with any pluggable car built now or in the foreseeable future.
If you see units for sale for $300 on Ebay, keep in mind that they are mis-wired and will not work with the Leaf's charge timer. The one I bought worked fine without the timer, but I had to send it to Clipper Creek for repair, as the seller found the same issue with all the ones he had.