After Xbox Live and PlayStation Network we are not that surprised, are we?
You will need a Nintendo Account to use online features of the upcoming Nintendo Switch console. All Compatible co-op and competitive modes within the starting titles will be available for free when the hardware releases in March 2017.
Unfortunately, the online gameplay part of the Online Service will be paid starting from Fall 2017. This is when the service will be expanded with an online lobby and voice chat, as well as monthly game download (free NES/SNES games added every month with newly-added online play). “For free for a month” wording suggests that these titles might become unavailable after a month and will need additional payment.
Exclusive deals are also mentioned, but you’ll have to wait for further details. Here’s an official summary of the differences between subscribers and non-subscribers (taken from Switch’s official site):
For all the latest news about the console and its games you can follow Nintendo Switch tag.