As for the Switch, Tabata is unsure if the game will even run properly on the hardware. Nobody has run the tests yet, and despite many on the Final Fantasy XV team being Nintendo fans, no plans have been made to make the port a reality.
Nope, don’t even bother asking anymore. If it’s supposed to happen, it’ll happen. The Switch is much less likely than a PC port at this time. However, Square Enix has not yet given up on Nintendo yet, dedicating many Dragon Quest games to the console instead.
Article source: https://www.technobuffalo.com/2017/02/08/final-fantasy-xv-director-focused-on-project-scorpio-no-plans-for-the-switch/