From Nintendo Everything article:
Before Switch was announced, no one could have predicted how much support Bethesda would be giving the system. The Elder Scrolls V: Skyrim got things started late last year, followed by Doom. The Wolfenstein II also just launched on the platform today. Fallout Shelter was released earlier in the month, and The Elder Scrolls: Legends is planned for later this year.
Gamereactor interviewed Bethesda’s Todd Howard at Gamelab this week. When asked if there’s interest in bringing over a mainline Fallout, he said:
“Well there’s definitely interest. It’s not something that we are exploring right now. We think Switch is a great platform – it was the first time we really worked closely with Nintendo on Skyrim – and really, really great experience and we’ll certainly be doing more things there in the future, but right now it’s not a mainline Fallout 4.”