The only thing really close that I could find is that the Aztechnology subsidiary Genetique works on fertility stuff. But then that's Genetech, not Nano so it doesn't help you much.
It's certainly within the realm of possibility to do what you're suggesting, but it looks like you'd have to do a lot of the nitty gritty work yourself.
Me? If it's plot stuff, then the details aren't that important in the case you describe. A simple "they used some kind of nanotech organisms to get her pregnant with stuff from dude and chick" is enough to explain what's going on. The only reason you'd need more detail, to me anyway, is if the tech were the center of the plot, rather than the pregnancy (for example if the runners were being hired to steal it; although even then a simple "that's the jar with those fertility nanites in it would probably do the trick

).
As far as legal issues, not sure that you're going to find much in canon that directly addresses that. The bonus there is that whatever you say the law is goes. I could even see certain stricter jurisdictions calling that rape, perhaps even of both parties, with the culprit being the entity that controlled the nanites/process.