(thread resurrection)
Seems the OP bought an '11 Leaf and lives in the Seattle area.
https://mynissanleaf.com/viewtopic.php?f=27&t=30857&p=618010#p618010
https://mynissanleaf.com/viewtopic.php?f=27&t=30857&p=618151#p618151
In my driving of BEVs as my primary car since end of July 2013 and now having only BEVs since end of Jan 2019, I've never had any EVSE that can accept and take advantage of NEMA 5-20, 14-50, 6-20 nor 10-30.
The only EVSEs I've had were the stock L1 120 volt NEMA 5-15 EVSEs they came with, which I almost never used. Yes, they could plug into NEMA 5-20 but it still would only draw 12 amps max. Heck, I've never even plugged in the one that came w/my leased Niro EV.
(I guess there's one exception to what I said. The L1 120 volt EVSE that came w/my former Bolt has been widely reported of being able to run at 240 volts despite its labeling w/o sustaining damage but its output would be limited to 240 volts * 12 amps. I never bothered making or finding and adapter as there was no need.)
OP might have a tough time finding NEMA 5-20 and 6-20 in the wild that would be reachable to a Leaf w/o an extension cord. From checking Plugshare, there's very little NEMA 14-50 in the Seattle area that's not residential. By the point where you might have to ask/beg someone at home to use their NEMA 14-50, you may as well include residential J1772.