I doubt it. I could see shareholder's pressuring Nintendo to allow a customized GamePass on Switch (one that only include Microsoft exclusives and not the revolving door of timed GamePass releases). Then everyone gets what they want. Microsoft makes money from subscribers, Nintendo gets a cut of the profits of Gamepass for games they would have never been able to sell anyway (like Halo or Grounded), and Nintendo gamers get to play a ton of new games wherever they want.

I could even see Ultimate including not only Xbox and PC but also Switch. Charge $20 a month or something and you can play the games literally anywhere.

This would be a far bigger get than a major studio acquisition and doesn't have the downside of those studios falling apart down the road like some have mentioned already.

No. So called "Stimulus Goliath" moves are Microsoft's thing, much like how IP moneyhatting is Sony's thing. Nintendo's thing is making their own IP and then having a classy dev work on it and give it a good shine.

Nintendo will not buy another studio and they don't have to.
Nintendo has already the biggest first party output of the big three console manufacturers plus Microsoft's decision to acquire Bethesda changes nothing for Nintendo, Bethesda games were never system sellers on Nintendo consols.

I don't see them buying up some AAA publisher like Microsoft just did.

That said, a smaller studio could be in the cards. No publisher since Nintendo seems to largely prefer using it's own IPs to those from bought studios (apart from Bayonetta of course)

With that said, If I had to choose some studio to buy, it would probably be WayForward games, as Shantae, Mighty Switch Force and Vitamin Connection really fit well with Nintendo's own IP in my opinion.

Historically, Nintendo has not been about big acquisitions.  I personally think they need to invest that big pile of cash they are sitting on like a dragon, but they probably aren't going to use it to make a big acquisition like Microsoft just did.  Generally Nintendo seems to like to build their company slowly and carefully.  They gradually train new teams and build relationships with other companies and either invest and/or buy a company that they already have a good relationship with.  For example, right now Koei Tecmo is a decent candidate (or maybe just some of the development teams that fall under Koei Tecmo), because it seems like they have been working closely with Nintendo lately.  Nintendo has also been using their money to simply get other studios to make games using their IP.  But I suppose that is another way to build relationships with other companies.

The way history played out, Nintendo could always afford to build their company slowly and carefully because they've been in video games since almost the beginning.  Sony and Microsoft entered into an already robust market, so they had to aquire development studios just to compete.  Even all of these years later, Sony and Microsoft have to make bigger acquisitions, because they are still significantly behind in first party output compared to Nintendo.

I believe the last time Nintendo attempted to purchase a big publisher is when they supposedly tried to buy Namco in the mid-2000s. It didn't happen and I think the consolation was Monolith Studios. It seems Nintendo has never fully wanted to get away from Namco as they own nearly 4 million shares in the company. It's unlikely they will attempt again as Namco is larger now than 15 years ago. So they last bought a studio in 2007. Nintendo likes to publish exclusive deals with 3rd parties. Work closely with them and let them make a spinoff, remake, or new entry in a long-running IP. Metroid. Zelda and more. Why buy SEGA when they can partner with them on Bayonetta? If SEGA one day cannot partner with them or just says no on Bayonetta..fine they create new IPs with PG like Astral Chain or Wonderful 101. Just as an example,

Won't happen. Nintendo is far too conservative, they are not only an old fashioned Japanese company but they are a Kyoto based company and Kyoto business culture is even more stringent and strict than say Tokyo. They like being a small company employee wise. Makes it easier to micro-manage the company.

If they didn't own Retro outright I think they probably would have dumped Retro too, lol. That studio has been given a lot of chances and come up short in terms of delivering a finished product in an acceptable time frame. 

What Nintendo does do is they're basically using Bandai-Namco and Tecmo-Koei as outsourcing studios.

Nintendo should have bought (or helped) CING when they struggled or when they went bankrupt.

I miss games like Hotel Dusk, Last Window, Again and Another Code.

They are condemned to indefinitely grow in eating studios or they will one day be absorbed by one of the GAFAM.

No Nintendo tends to only buy studios they can build up to their liking as nurtured talent fits into the company's philosophy a lot better.