I went with 75m-100m. Basically I'm thinking like 90m.
If they hadn't completely screwed up all the pricing and had Mario coming out on launch day to drive word of mouth from launch (though Mario Kart looks incredible enough to do that to a lesser extent) I woulda thought 120m-130m given how great the system looks.
If they admit their pricing mistake and fix it soon to make Nintendo affordable again then I'd say it can do 100m-110m, but as things stand I don't see that happening. At these prices some people won't be buying ever, lots of parents won't be buying one for each kid again (or won't be doing a docked Switch + Lite combo for the kids) and lots of people won't be buying the original model and then upgrading to a later OLED model. Just too expensive for most people to do that sort of stuff at these prices. One more possibility is if they come out with a Switch 2 Home that's reasonably priced, like $300, and they don't wait too late in the gen to do it, that could drive a lot of sales and I think would at least push them over 100m.
If they do nothing to fix things and just go with the Switch strategy of keeping the same cost forever, it's going to be a much slower gen for Nintendo and maybe we'll see them fix that mistake next time around, like Sony did after PS3. Right now Switch 2 is looking like Sony's PS3 debacle. Though Nintendo at least won't have to worry about a Wii-like competitor dominating the space for 2-3 years, but on the other hand Nintendo doesn't have nearly the committed base that Playstation has, so I think those two things even out to give Switch 2 a similar drop in sales that PS3 had from PS2.