Download the latest for your version of Atmosphere. Place them in the /atmosphere/ folder on your SD card. Reboot your Switch into RCM and relaunch the CFW. Step 3: Use a Different Installer Some installers are more "forgiving" than others.
I can provide specific instructions for your preferred tool once I know those details! the nsp file is missing a program-type nca
Have I tried installing via using "Tools > Run MTP Responder"? To help you get this running, could you tell me: Which installer are you using (Goldleaf, Tinfoil, etc.)? What is the file size of the NSP you are trying to install? Are you sure this is the Base Game and not an update? Download the latest for your version of Atmosphere