A nisc is an evolution of risc where the cpu has no instruction set nor microcode.
Programs are written in nanocode with direct access to internal cpu components pins.
Such programs resemble more to hardware description languages like verilog, and compiling a C program for that kind of cpu requires special techniques (but such cpu still carry out instructions).
The main idea is the place used by traditional cpu control units are left for using more other components providing more performance or less electrical power consumption.
When I tried to search for an implementation, I only saw academic papers or lessons mainly teaching how cpu works. Except a patent about the ɴɪꜱᴄ idea but which is held by an individual (not a company).
By commercial, I mean used in an end‑user device (such as a desktop computer or an infrared remote control) or used in a performance oriented server.
If such implementation exists, it’s datasheet would be a bonus.
This question isn’t too broad as it’s obvious such cpu would be a commercial catastrophe (perhaps with few exceptions which is the aim of that question).