On macs the override goes in the folder "Knights of the Old Republic" you do not need to show contents and navigate to the Data folder.
On my mac the Kotor folder has:
The App, Override, data, streamwaves, modules, TexturePacks, streamsounds, streammusic, rims, lips. chitin.key, dialog.tlk, patch.erf, movies, KOTOR Version History.rtf
Unless this is the app store version of the game, that is where your override should be. If this is from the app store, I've heard there were some weird glitches and other things with the app.
If you don't mind posting a link to the mod I can see if I have any trouble on my end.
Hope this helps