In the film's official novelisation, the plateau (where the Space Jockey ship was found) was discussed. Ripley's plan was to 'glass' the colony and the ship.
I say we take off and nuke the entire site from orbit and the whole high plateau where we originally found the ship that brought them here. It’s the only way to be sure.
In the film, this bit of the conversation appears to have happened off-screen.
That being said, I think we can assume that the catastrophic destruction of Hadley's Hope was enough to take out the ship since the Company had to rely on harvesting Ripley's DNA (from the Fury facility) in order to get a viable sample of xenomorph DNA. Had the ship survived, they could have just gone there to get some eggs.