Prediction: NX will be first console where Mario and Zelda release together

[Soundwave]

Probably not together since that would be overkill, but Mario/Zelda games have launched within under a year before.

Super NES - Super Mario World (August 1991 US), Legend of Zelda: A Link to the Past (April 1992 US)

Wii - Legend of Zelda: Twilight Princess (Nov. 2006), Super Mario Galaxy (Nov. 2007)

GameCube - Super Mario Sunshine (July 2002 JPN), Legend of Zelda: Wind Waker (Dec 2002 JPN)