"Nanotech" was a click bait buzzword before "click bait" was a word. We have it, and its fulfilling many promises, in the form of integrated circuits. We had those but larger when the promises of "nanotech" were being sung.

We have "nanopore" filters and they're doing fun things in chemistry and medicine.

As for mechanisms, we have things like accelerometers and microphones and DLP image chips ... useful but complicated mechanisms have maintenance requirements and that becomes a problem when all we can do at that scale is "fire and hope" manufacture. Try to make lots of a thing, hope some of the things come out properly, dont worry about the ones that dont.

i dont think we'll have "nanobots" for a long, long time. Cultured microorganisms will be easier, we're not going to beat proteins by building tiny metal brakes and welders: metals aren't the same at that scale.