Most likely there is no real C-limit on Leaf (what do 8 bar Leaf owners see when QC-ing?)
Leaf1 just doesn't ask above 125Amps. Maybe the wiring is not made for more.
What we do know that maximum voltage for any cell is 4,13V and that is the main
limitation above 1/3 charge state.
Even at really low SOC and ideal temperatures it is hard to get over
125A on 24kWh pack. That voltage limit is reached really fast especially if
temperature of the pack is not ideal. And this is why all EV-s taper while QC-ing.
24-30kWh pack on 50kW 125A charger is pretty much maxed out.
Teslas 70-90kWh packs on 135kW 330A are pretty much maxed out.
We can expect Leaf2 and Tesla3 both suck 100kW from chargers as MAX speed.
Even if Superchargers are able to give more - battery will not be able to take that.
Kia Soul EV with 30kWh pack did charge few minutes faster on 100kW ChaDeMo.
Is it worth it? 2x power to lose 5 minutes on 0-80% time
100kW charger does make sense only for packs above 50kWh.
This is not Nissan specific.