How to Set Up a Router's Port Forwarding for a Nintendo Switch Console
Apparently you only _need_ to forward 45000~65535: https://www.reddit.com/r/NintendoSwitch/comments/6qjhjy/i_ha...I went through this when setting up the switch to talk to someone behind heavy NAT over the holidays. 45000+ worked for me.....which makes this even more ridiculous if it never uses them.