Sometimes, despite your best efforts, an NSP file is unrecoverable. Signs you should delete the file and find a new source:
Which are you using (e.g., EmuDeck, Tinfoil, DBI)? the nsp file is missing a programtype nca work
Ensure your SD card has enough free space to accommodate the full size of the game. Sometimes, despite your best efforts, an NSP file
Ensure your encryption keys match the firmware version required by your game. despite your best efforts
There are three primary reasons you might see this error: