Romslab is a website that operates in the piracy ecosystem. It functions as a repository for these NSP files. These sites often face takedown notices (DMCA) from Nintendo but frequently resurface under new domains or redirect to file-hosting services.
GameFly (in the US) rents Switch games by mail. You could play and beat Ben 10: Power Trip! in a month for ~$15. Ben 10 Switch NSP Free Download Romslab
While not a "system seller," the game is often regarded as a solid entry-level title for children. It lacks the depth of AAA action games but serves as a faithful interactive episode of the cartoon. Romslab is a website that operates in the piracy ecosystem
You have better, safer, and often cheap options: GameFly (in the US) rents Switch games by mail
NSP stands for Nintendo Submission Package. It is the file format used by the Nintendo eShop to distribute digital games.