You can find updates and DLC for in NSP format through various community-driven archival sites, though these are not official Nintendo distribution channels. Installation Basics
Q: Can I download Sonic Origins for free on the Switch? A: Yes, demo versions and NSP files are available for download, but purchasing the game through official channels is recommended. Sonic Origins Switch NSP Update DLC Free Do...
If you meant something else — like a technical guide for backing up your own purchased game (using homebrew on a modded Switch) — let me know, and I can explain the within fair use boundaries. You can find updates and DLC for in