You'll simply add your existing Discord account to a My Nintendo account.
The benefit here is that it has the same kind of voice chat, messaging and community features you'd get from PSN or XBL. However, unlike Wii U's Nintendo Network, you're not isolated from the rest of the gaming community.
No insider info - just a good idea I think Nintendo can and will follow through on. Not to mention - huge win for Discord as well.
I predict NX launches in 2017 - not 2016