Distributing or downloading pirated software is illegal and violates the game's terms of service.

Connecting a console with modified software or pirated games to Nintendo’s servers typically results in a permanent hardware ban from online services.

If you are looking for the official game, it is available for purchase on the Nintendo eShop and at major retailers like Target. Русификация игр Nintendo Switch - 4PDA

The "NSP" extension is a Nintendo Submission Package file format used for installing games on modified (jailbroken) Nintendo Switch consoles.