Because the Nro2Nsp is not working with 12+, so I tried to make a tool to do it by myself, based on hacBrewPack, for Windows
Step by step
1) Download https://gitlab.com/martinpham/NSP-Forwarder/-/archive/master/NSP-Forwarder-master.zip
2) Extract to a folder on your Desktop, eg: NSP-Forwarder...