It's not a "copy" as the model is quite distinctive Chinese and Nason never made anything like it. Also, Nason pieces (from the 60s not the 30s) have all over aventurine on black, not a few isolated specks as the Chinese.
It is a straightforward misattribution and I think you can just tell the seller. If they will not modify their description you can still post the link here (hehehe...)