While individual downloaders are rarely sued, distribution is actively pursued. Uploading or seeding the Okinawa Rush ROM could expose you to copyright claims.
Assuming you have a Switch running Atmosphère CFW and have legally dumped your own copy of the game, here is how to apply the update: Okinawa Rush ROM NSP UPDATE - Switch Game
This write-up is for informational purposes only. Please ensure you have the right to play and download games by checking the official Nintendo eShop or game publisher's website for availability and purchase options. While individual downloaders are rarely sued
NSP files are containers. Hackers can package executable code that installs spyware, ransomware, or crypto miners on your PC when you extract or transfer the files. Even “scene-released” NSPs are not always safe. Okinawa Rush ROM NSP UPDATE - Switch Game