Even with today's nanoscale technologies, good legislation or regulation will not be easy to design and implement. Given that commercial use of nanoparticles has been going on for years now, it is probably not too soon to begin devising a well-considered regulation or two.
However, it would be highly unfortunate if focusing on the concerns about nanoscale technologies distracted attention from molecular manufacturing risks.
Nanoscale technology risks are of familiar types (though, of course, varying in detail and severity). Molecular manufacturing, on the other hand, will create technological capabilities that have never existed, of a power that easily could be destabilizing on a global scale. New kinds of problems will be created and new kinds of regulations may well be needed. Research into these implications should be an urgent priority.
With any technology, hasty regulations are likely to be inefficient or even counterproductive. Ongoing studies -- of both near-term and long-term nanotech implications -- will reduce the risk of ill-considered regulation in a panicked response to the inevitable unexpected problems.