Did I do that....?

Well after running around and setting off more nukes (which isn't as interesting as it sounds), I got to a point where Ulysses explained in his roundabout and pseudo-philosophical way what is the point of the DLC.

Turns out that at one point the Courier had a trade route through "the divide", and a town sprang up along that route. Ulysses was a Legion spy who posed as a courier, and tracked the Courier to this town and he thought it was a nice place to live and not connected to the NCR or legion. Then the Legion had the Courier deliver a package to the town, and in that package was a device that activated all the underground nukes in the area after the Courier left.

So Ulysses blames the Courier for destroying this place and wants to deal with him, but he's still honor bound to Casar not to kill any other couriers (weird priorities), so he wants to see if the Divide can do it.

Also I found that this DLC has one other new enemy, glow in the dark tunneling lizard people that look like the new Silurians from Doctor Who. They go down in one hit with my power glove, but they also have quite a knock-back and do a fair amount of damaged, so it's get them before they get me.