I'm pretty sure you can't use a GTX 1060 on an ARM device. They'd have to create a custom chip.

I'd rather get a Switch Mini

Why not? Technically all you need is a PCIe slot and drivers. Apparently there are ARM motherboards with PCIe slots, so that leaves drivers, which are a software issue (i.e. no custom chip required). That said, I can't imagine Switch using either a regular motherboard of any sort or having a PCIe slot.

Nintendo is not fast enough for that even if Nvidia would be.

It really all depends on the success of the pro and scorpio how the future will turn out hardware-wise if peole want and support it, it will happen

Nintendo New Switch

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I think the most Nintendo would do is a DS > DSI, i personally can't see them doing a PS4 Pro-esque upgrade. We shall see though!

I was more thinking in terms of another tegra processor. This is not a laptop with a external GPU option, unless Nintendo came up with something, 99% sure it won't happen.

Well, Nintendo has precedents of both selling upgraded versions (New N3DS) of handhelds and selling add-ons that upgrade home console performance (Expansion Pack, N64 DD). I don't see why they wouldn't do a "Switch PRO"

100 % - 2018 a new switch modell with better battery pack (akku) and bigger screen. So: Yes. One year later a new Swich-Upgrade. 2019 - stronger switch-hardwareUpgrade then.

Well things like the N3DS were fairly minor upgrades, and things like the Expansion Pak were typically included in the game, so we've yet to have Nintendo actually come out with a new version of a console/handheld with it having a big power leap. Having said that, Sony/Microsoft didn't do that before as well so no reason why Nintendo can't!