While I love the idea of a 3DS Jam, unfortunately you aren't allowed to distribute software made with the Unity 3DS port, as that software and it's exports are distributed under NDA, and doing so would be breaking that NDA opening you up to potential legal issues.
I highly recommend instead you have people use the open source homebrew toolchains, software and games made with those can be freely distributed with no issue whatsoever.
https://www.3dbrew.org/wiki/Main_Page 3DBrew is a GREAT resource for developing homebrew titles.