The Leaf is NOT adjustable. Unless the battery is almost full it will charge at the maximum of the Leafs built in charger, 12a 120v 16a 240v for the old Leafs or 3.6kw models or 27.5a @ 120/240v for the 6.6kw Leafs. For that reason I'd definitely not suggest a portable EVSE over 16a you couldn't dial down. For sure for use on 120v and the 40a model with a 6.6kw Leaf. Not many 27.5a 120v plugs/circuits you'd ever run across. I guess it might be OK with the 16a model as 20a 120v circuits are readily available in just about any home and in commercial buildings and using the 16a model in a 3.6kw Leaf would only charge at 12a @ 120v anyway, which any 120v circuit should be able to handle(without any other large loads).
Not sure how this EVSE compares with the OPs, but for $10 more I'd sure take the 25' cord vs this EVSEs minimal 16'.
https://www.amazon.com/New-Maxx-40-40-a ... ev+charger
The 16a version looks interesting, again a rather short cord but does have a nice display which similarly priced models on Amazon lack.