There is a chorus effect plug-in available here: https://forum.audacityteam.org/t/chorus-effect/26335/1
To install the plug-in, download the plug-in (MultiVoiceChorus.ny) and put it in the Audacity plug-ins folder (on Windows the Audacity installation folder is usually in “Program Files” and the plug-ins folder is inside the Audacity program folder.
After “installing” the plug-in, restart Audacity and the new effect will appear “below the divider” in the Effect menu.
Let us know how you get on.