I've not heard of a way to reset the shutter count but Nikon's website do say
"There is no way to accurately tell the total number of
times your camera shutter has released. While there are
third party software applications designed to read a cameras
shutter count, this number is not always accurate because
the shutter release times may be reset by firmware updates,
or reset in the Service department if certain parts are
replaced or other operations are performed."
Have you checked it yourself or did the seller tell you? If they've had it back to Nikon for replacement parts then it's possible the count may have been reset but it's fairly unlikely - maybe the previous owner carried the camera everywhere but didn't take many shots?