Hi everyone! So someone replied to me on reddit with a fix! I don't know how permanent it is but it worked for me!
Simply open your terminal (for Mac users press Cmd+Space and type "terminal") then paste the following code:
chmod +x /Applications/Twitch.app/Contents/MacOS/TwitchAgent.app/Contents/MacOS/TwitchAgent
Then relaunch your Twitch and the Mods tab should show up (I had to refresh once for it to work).
Hope this works for you too!
Solution for me. Thanks