Well, it should suffice for the carnage to have taken place where we saw it take place - at very low orbit over Vulcan. The horizon would then take care of shielding Nero from the approaching fleet, and later the debris field from Pike's approaching ship. Certainly it would be Nero's decision where to face the fleet: he deploys his drill only well after the fleet leaves Earth, and could easily calculate a position that gives him optimal protection by the horizon.
It's not a proper datapoint on sensor performance, then. Especially when Nero's noisy drill makes sensing difficult in the first place.
Lol - but the problem is that if ships can't detect debris close to a planet they are going to crash into ships in orbit. Kirk was just lucky that he didn't warp into a Section 31 secret base in Trek 09.