[FATALTYONE]

Thanks for posting a debug log. It shows that the nes30 controller(s) aren't being detected by the joystick add-on. You can tell this by searching for the word "joystick" in the log. Is the joystick support add-on enabled? Maybe it's an operating system issue. Hard for me to tell without being able to test on desktop linux using a physical nes30 controller.

Before every major release I go on a buying spree and pick up 10 or so controllers to test with Kodi. As we get closer to the Leia release (prolly around january or february), I'll get a nes30 controller and get it working in Kodi and LibreELEC.

The problem is not only with the nes30 but also with the chinees arcade usb pad and cheap chinees snes controller.
So far i now the joystick add-on in enabled i can map the controls but not ignore de kodi one
And i have a clean install on my pi3 (Milhouse built) with only emulators on it to test it

Snes controller
http://sprunge.us/KgRP
Arcade controller:
http://sprunge.us/FPcJ