This is less common, but you can decompress an NSZ back to NSP, then use a tool like 4NXCI to convert that NSP into an XCI. However, emulators like Yuzu and Ryujinx have native NSZ support, so XCI conversion is rarely necessary.
Even with perfect files, users encounter problems. Here is how to fix the most common Super Mario Odyssey XCI/NSZ errors. super mario odyssey xci nsz
If you have a Switch with custom firmware (Atmosphere is the current standard), NSZ files are a godsend. This is less common, but you can decompress
With emulators adding direct support for newer formats like XCZ (compressed XCI) and with Nintendo aggressively targeting distribution sites, the landscape is shifting. Even with perfect files, users encounter problems
For Super Mario Odyssey, the best long-term archival format is likely a base NSZ with the 1.3.0 update and Balloon World DLC merged into it. This results in a single file that is smaller than the original XCI, fully updated, and playable on both emulators and CFW via installation.