I tried that. Didn't work for me. I went to the 'waypoint' page, selected the bottom right button, and then hit "select". I only get the option for spelling out a waypoint name of my choice.

The obvious thing to check first is whether a GPS signal is getting to the unit. I verified it had a GPS fix and it was giving me guidance information to a selected waypoint, so the unit was getting the necessary GPS data to generate a 'nearest' list.