Human brainstems do not handle telling the truth
Except whenever the SUPER SLUG is attached to it...
Yeah I got nothing. We could stretch the logic barrier and say that it attaches to the brain stem and overloads the host's sensory data, causing exceptional pain and under the torture he might
be forced (assuming Pike wouldn't have the resolve) to give up the information.
But that is really not what the line was implying. It was supposed to be a more sinister looking "truth serum" plot device and unintentionally further cements Nero's image as that of a Bond villain's.
It is the latter. He knew he had gone back in time. The ludicrious aspect of the story though, is that he waited for Spock to show up in the past as well, somehow knowing that he would eventually turn up (which was 25 years later IIRC). I guess it never occurred to Nero that Spock could have gone back centuries, or possibly into the future?
Nero did eventually figure it out though. Through some form of crazy mathematics, they were able to pinpoint Spock's entry in space and in as to provide for an easy capture.
The part I did have a problem with is why Romulus wasn't evacuated before the supernova destroyed it- aside from the fact that they had time to do so considering how they could plead Vulcan for help and wait for Spock to prepare and get there, they shouldn't have stayed there anyway because a Solar System without a sun is going to have a slight weather problem. =P
My only answer would be to read the synopsis to the tie-in comic.http://en.wikipedia.org/wiki/Star_trek_countdown
It seems to imply Romulans as a whole weren't the ones asking for help, two individuals (Nero and Spock) were both shot down by the council. Presumably, the council viewed the supernova (at that point in time) as a negligible threat to the planet. This would also explain why Spock was late to saving them as it was expanding even faster than he
predicted. Basically, it somehow caught all parties off guard.