So I have been trying to get Kodi to play movies from my USB hard drive but I can't see to locate it on my Kodi.
I can play it through ES File explorer but I am not able to even get the HDD to scan via Kodi. Can someone point me to the correct path on Nvidia Shield for external drives?
Use SPMC instead. It's a Kodi fork designed specifically with Android TV in mind. You can get it from the play store, just say "SPMC".
Not only is it better than the official Kodi app on Android TV for various reasons(voice search support!), it also automatically adds attached storage devices to your Videos -> Files menu, making everything incredibly simple to set up.