The post game log from irc tells the story of this one:
BigB: How the hell did you manage to nuke her
Hepatia: Well I'll tell you... I colonized the natural border planet of 20,20 and tricked 20,20 20,21 21,24 and 21,22.
Hepatia: At this point she could see 20,20 and I could see 19,20 and that was the extent of it.
BigB: how many updates
Hepatia: She did not trick I don't think, she decided to use a stargate.
Hepatia: Total?
BigB: yeah
Hepatia: 50 but she pretty well gave up before that.
Hepatia: Anyway we built up a little but due to me tricking and not using a stargate, I hit BR 3 first.
Hepatia: I tested her BR just to be sure with my last 4 BR 2 ships against 5 of hers.
Hepatia: She got a little overconfident, kept building up, and was surprised I think when my BR 3's wiped her fleet out and nuked her frontline builder.
Hepatia: Hitting BR 4 first got me her next sys in line.
Hepatia: After that all I had to do was not screw up.
BigB: heh
Hepatia: She was building tech for a while, or so I thought, but I just kept pounding at her and my sweeps kept surviving.
Hepatia: My sci ships kept biting the dust, which slowed me down a bit.
Gnu: sounds good. Once youve got the edge, just grind away...nothing fancy
Hepatia: Not really. I think I had the map advantage actually.
Hepatia: It was slight, but it had to do with the critical opening moves.
Hepatia: Even though my systems were further away, I was able to channel more ships to the front due to the linearity of my side.
Hepatia: Her scis that went s and w at up 2 were not a factor in whether I could get her off my back long enough to trick.
Hepatia: I do think that she should have tricked when she saw that I was.
Hepatia: Not sure what was going on on her side at that time though.
Hepatia: You might want to note that systems 21,21 21,22 and 21,23 were terraformed by 40 each and 22,23 by 30. Lets you know what map I was looking at in the opening.