Stick to the official stores. Your computer (and your wallet) will thank you.
Emulation is legal, but downloading copyrighted game files (XCI/NSP) from the internet violates copyright laws. This article is written strictly for educational and informational purposes. To play Super Mario Party Jamboree legally on a PC emulator, you should dump the XCI file directly from your own legally purchased physical Nintendo Switch cartridge using a modded console.
If you are planning to dive into this game, and prepare for a truly monumental party.