Apparently, Nintendo will be using the industry standard USB-C adaptor and port for their upcoming Nintendo Switch system, if these listings of accessories for the console-portable hybrid on EBGames Australia (via NeoGAF) are any indication. The charging cable will apparently be 3 meters long, and be USB-C for the end that goes into the tablet, and USB-A (or the traditional USB that we are all familiar with) for the other end- meaning that charging the system should no longer be a hassle.
This charging setup has multiple benefits- USB-C is insanely fast, meaning that charging should be quick, unlike the arduously slow charging times on the Nintendo 3DS line and the Wii U Gamepad. USB-C is also an industry standard, meaning you should be able to use any charger you have lying around the place to charge your tablet. USB-A on the other end also means that you can plug the Switch into anything to charge it up, since USB is as universal a port as there ever will be. Finally, USB-C is very fast at data transfers too, should that be an avenue Nintendo ever fees like exploring.
It should be noted that the listings on EBGames Australia’s site have since been deleted- which seems to indicate that they were true leaks. The Nintendo Switch currently is slated to launch worldwide in March 2017.