You can download the games directly to your microSD card.
If you are searching for an NSP (Nintendo Submission Package) file online, you are likely venturing into the world of "Grey Market" sites. Here is why that is a bad idea: Batman Arkham Knight Switch NSP Free Download R...
Buying the game ensures that developers continue to port high-quality AAA titles to the Switch hardware. Conclusion You can download the games directly to your microSD card