In order for us to observe biological (as opposed to intelligently designed) nanoscale engineering in the wild, it must be possible for it to have evolved.

If you look at genetic algorithms, they don't find all, many, most, or the best solutions - they find solutions which have paths of a certain type leading to them. You could call these paths axis-aligned, where each gene corresponds to an axis. E.g. http://www.caplet.com/MannaMouse.html

The applet only has two genes, and so doesn't have any of the changing-numbers-of-genes phenomena that we expect in the real world, but it gives a rough sense that evolution works in a specific, simple, and not very smart manner over the fitness landscape.