Nanotech being defined as: manufacturing on the scale of individual molecules and atoms.
As has already been pointed out, this is will work essentially like all biological organisms work. Robots move chemotacticly, they are designed to repeat specific structures, they have specific cytokine style on-off switches (or "throttles), they work relatively slowly. Complex structures like nano-electronics are "painted" on to their substrates like Michealangelos, succesive baths of specially tailored, cultured nanites, moderated by their chemical toggles. Larger scale industrial processes can speed work up using a hybrid approach of nanites and gravatics/advanced magnetics.
[Examples:] how do they build a structure at TL15? What kind of materials are they using? How are they deployed? If you tell me that they still spend time hauling around huge loads of gravel or something, it will raise an eyebrow.
How do anagathics work?
How do they make reliable sealed containers for refined hydrogen?
What is crystal iron?