Not a nanobot, but perhaps another tiny incremental step toward positionally controlled chemistry. I can't get to the core Nature article, but it looks like they make a DNA tile cassette, which they can insert a variety of DNA tooltips into. They probably get ~1-10 nm positional accuracy between tooltips. Not precise enough or controlled enough to do diamond mechanosynthesis, but possibly an interesting route to bootstrapping into that kind of technology. As per usual, the biggest problem is that DNA isn't particularly stiff, making it hard to apply the kinds of forces at picometer precision that seems necessary for the sci-fi nanotech visions. Variations of this technology may prove useful in designing and building/folding artificial proteins or biomolecules. With biomineralization, that might eventually provide the stiffness and strength necessary to start beating nature at this mechanosynthetic game.