It looks like you're trying to find a (likely a guide or technical document) related to running Nintendo 64 games on Nintendo Switch Online — specifically for the Japanese NSP version, and perhaps aiming for "better" performance or emulation.
Navigate to the Nintendo Switch Online section of the Japanese eShop. Download the N64 app (it will have a slightly different logo). nintendo 64 nintendo switch online nspjp better
If you meant a on emulation accuracy or N64 architecture on Switch, that would be rare — most useful docs are from GBATemp, Reddit, or GitHub. It looks like you're trying to find a
Go to Nintendo's website and create a new profile with the region set to Japan . If you meant a on emulation accuracy or
Users with custom firmware (CFW) on their Switch (e.g., Atmosphere) can install the dumped NSPJP file. To do so legally: