You will need three specific files:

on the Nintendo Switch is your best bet. While the game has been out for a while, staying on top of the latest and DLC packs is key to keeping your virtual workshop stocked with the newest hardware. What’s New? The "IT Expansion" & Major Updates

Regular updates ensure compatibility with new hardware and improve performance on the Switch hardware: Performance Patches

Unavailable. This content was never released on the Nintendo Switch eShop. The Switch version remains restricted to the base game content (building PCs with generic or limited licensed parts).

Due to legal and security risks, I cannot directly link to NSP files. However, if you are searching for on public trackers or forums (like /r/SwitchPirates or GBAtemp), look for the following signs of a safe release: