Async compute has been a part of this generation since 2011 when AMD GCN GPUs hit the market, it seriously wouldn't surprise me if it is Turing, I had the odds at 1:3 before the Nintendo job offer, afterwards I'm putting it at 2:3, with Pascal being the other likely choice.
One thing that I'm looking at is Tegra's timeline, Tegra always seems to get a release of the current GPU architecture within a year of their desktop GPU's release, and Turing had its release last year, so by the end of this year, Nvidia should have Turing Tegra hardware available.
I know that the Switch Pro had a Tegra X2 in it and last year changed to a new chip with a more modern ARM CPU, that would line up with prototype Turing Tegra hardware. Another reason to look at this is because the Tegra X2 used in the Switch Pro was overclocked, that clock would have to be 1.6ghz or more, and offer ~800gflops. Again it was changed out around the same time Mariko hit Switch firmware with 5.0 in March last year.
If they want a device with 800gflops or more, they need more Cuda Cores, clocking a GPU that high is fine normally, but the Switch has a Battery being charged right next to it, so you can't draw that much power without the device getting too hot to hold, and that limits the use of pulling it out of the dock. If they are adding more Cuda cores and moving to 12nm, it's likely they go with a whole new GPU architecture, it also makes sense with the report I've heard of a new CPU architecture.
People are hung up on Nintendo hardware never being that new, but this is just a weird way to look at this imo, Turing is what Nvidia would want in their new shield tv and in the Switch, it also is cheaper than Pascal since it's already on the 12nm node, lastly it doesn't make the switch much more capable, it just has some interesting features, I mean in my mind a 944gflops pascal chip is more impressive than a 800gflops Turing chip, but I'd suggest that the difference between these chips are completely exaggerated by people in this thread, it's just a few naturally better features for a low powered device, like variable shader support and async compute, at absolute best it can offer a bit more than 25% performance, but the average will be lower. Again I'm not trying to say that for a fact it's Turing, but I'm leaning towards Turing over Pascal.
Just got to a part where he thought BOTW ran at 1080p so I imagine he's fine with how things are now.
Don't expect any game that's <1080p 30fps to get a 1080p 60fps jump, i think
FPS jumps beyond the target fps require more work than resolution bumps, but it often isn't difficult to do, but the likely CPU upgrade should be enough to achieve 60fps in games that might be limited to 30fps on the current Switch going forward.