Are there explicitly implemented limitations to EV chargers in the US so that only specific brands and even models can use them? Or is the leaf just technically incompatible to the chargers even with an adapter?
Yeah, the Tesla Superchargers were originally Tesla-only, but they are gradually rolling out access to other brands.
As for the Leaf, I’m not sure. It uses CHAdeMO, right? I don’t think there are any NACS to CHAdeMO adapters. You might be able to chain together a NACS to CCS1 with a CCS1 to CHAdeMO, but that could end up being a protocol nightmare.
Even if the chain of adapters worked and were recognized by the Supercharger, I’m not sure it would be worth it. Leafs charge slower than modern EVs, and given that many Superchargers bill based on time (not energy), it could end up being more expensive than other chargers.