Yeah, there's no reason to tell a developer the manufacturing process of an SoC, it's just not relevant to developing games for it.
I don't think it's completely impossible that Nintendo officially mentions it, though (or, more likely, allows Nvidia to mention it). Nintendo generally doesn't talk about specs, because almost any spec comparison against MS and Sony's hardware is going to be unfavourable to them. But, I wouldn't rule out them talking about one or two specifications which are favourable to them.
As a case in point, when announcing the Wii U, Nintendo didn't confirm detailed specs like GFLOPS or anything like that, but they did confirm that the system had 2GB of RAM. With the other systems on the market at the time sporting 512MB of RAM, the Wii U's 2GB of RAM was the one spec that made it look good, so it was the one spec that Nintendo confirmed.
In Switch 2's case, they're obviously not going to announce GPU TFLOPS or storage GB/s speeds, because they won't be favourable next to Xbox Series X and PS5. But with even PS5 Pro reportedly using TSMC 6nm for its SoC, then a 4nm process for T239 definitely would be a favourable spec next to the competition, so it's possible that they could consider it worth mentioning, even if that's just in an accompanying Nvidia press release.