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.”

https://nintendoeverything.com/bethesdas-todd-howard-on-future-switch-support-well-certainly-be-doing-more-things-there/

Why aren't the original Doom games there already? Doom, Doom 2, Final Doom and Doom 64. They would sell a ton if bundled together, just like all the other nostalgic compilations out there.

As long as Bethesda realizes Switch interest isn't just Fallout Shelter type games.

Yea not like they ported 3 AAA already in 8 months

So far Bethesda has released these:
DOOM
Skyrim
Wolfenstein II
Fallout Shelter

And these are the confirmed upcoming games:
The Elder Scrolls Legends

And based on their output, here's what I think is the most likely to happen on Switch:
DOOM: Eternal
Wolfenstein Youngblood (there are already rumors of a switch port for this
The Elder Scrolls Blades (the mobile game)

To be fair, Activision brought 2 CoDs to the Wii U and we all know how that relationship ended up.

But I think Bethesda will do fine on Switch.  Doom 2 and the Wolf 2 follow up are imo very likely.  Fallout 4 might not be planned now but I wouldn't be shocked if it shows up.  Remember Wolfenstein 2 wasn't even brought up for Switch when it was revealed at E3 2017 and well here we are.  

Lip-service again. Bethesda has just spent E3 like Switch barely existed. Until there's any significant announcement, they seem much more interested in PS5 than Switch.

Fixed.

Yeah the last three you mentioned are definitely coming in the future. Brand new games rather than years old ports. Much better

It's not lip service, and it never was. Bethesda actually delivered triple A games on Switch. Besides, all of the big Bethesda' announcements for Switch have been done in Nintendo's own directs, not in Bethesda's E3, as we saw last year.