For Pi Libreelec use `/storage/.kodi/addons/game.retroarch/addon.sh`
Arguments for Nes roms "fceumm "%rom%" $categoryID$ $launcherID$ $romID$"
You should download this file AEL Assets and use as a template or go to AEL settings → I/O → Import category/launcher configuration... and select the systems you want to import one by one
If I was you I ll have a good look here before setting up AEL...scroll down to AdditionalInfo-Advanced Emulator Launcher...All the info you need is there...
For I set this up yesterday and after some hiccups getting controllers and sound working, it's working great. EmulationStation works great, but I can't get AEL set up. All the examples of launchers I can find are wildly different from the structure on Pi Libreelec. I thought I had it figured out, but when I try to launch it, the screen just goes black and stays that way.
I'm obviously doing something wrong with the command or arguments lines. This is the only thing actually useful in the very tiny log
I have "Application" set to `/storage/.kodi/addons/game.retroarch/addon.start`, and "Modify Arguments" set to `fceumm "$rom$"`