This is a GUI tool to split .nsp files into parts sized for the FAT32 Filesystem. FAT32 is only able to handle files of a maximum size of 4GB.
The splitted parts are copied into a folder that is newly made by this tool, the original .nsp file will be left untouched. The save-location of that folder can be chosen via the GUI. The newly created folder can then be copied over to the FAT32 filesystem.