Unless you are running specific CFW configurations that require XCI for USB loading, stick with NSP. The conversion hassle rarely yields genuine benefits.
This is currently the most popular and user-friendly option because it features a graphical user interface (GUI). What it does: Nsp To Xci Converter Online
: If your goal is simply playing the game, DBI on GitHub allows you to install NSP, NSZ, XCI, and XCZ files directly to your Switch without needing to convert them first. Important Safety Warning Unless you are running specific CFW configurations that