Tegra X1+ is already technically small enough for a "Micro", if they like, while using a far more powerful SOC to emulate a Switch would be pretty inefficient. T239 should have extremely good yields and huge volume per wafer, while also being smaller than Tegra X1+, if it's on 4N. It isn't well positioned to be "binned", either. Basically, if they want a Micro Switch 1, they can, and if they want a Micro Switch 2, they can, the SOCs are already small enough to allow that if they really want. Just by following the designs outlined in their published parents and previous consoles, they could say, take the Lite, make the Z buttons in-line, make the control sticks circle pads, shrink the bezel, move the SOC so that it lay directly under the heat sink and line up the other circuitry down the side of the air channel, or even stack the fan over the circuitry. Micro-isation is more a factor of a lack of will. Lite isn't the best selling version already, while further miniaturisation using new designs costs money to research, design and tool manufacturing.
I would definitely be unsurprised if the NG Lite is smaller than the current Lite thanks to years of miniaturisation patents, experience, and T239 on 4N being smaller than the current Lite's X1+.