Try pulling the fuse for the stereo for a few minutes then putting it back in. It should cut power to the entire stereo and nav unit. The fuse is in the holder #4 per the diagram.
Unfortunately, the '13 Leaf manual per page 8-18 has you pry open a panel in the cabin to retrieve a fuse puller tool. I didn't bother with that as my 06 Prius has the correct tool an easily accessible location. You might find it easier/better to just buy a cheap fuse puller tool instead.
There are several long running threads about the crap 3G TCU upgrade where the TCU or something gets into a bad state and updates stop working along w/the notifications (e.g. charging stopped, unplugged, etc.)
I believe the references to 20 amp fuse below are correct:
http://www.mynissanleaf.com/viewtopic.php?p=513720#p513720
http://www.mynissanleaf.com/viewtopic.php?p=496194#p496194
If not, Google for site:mynissanleaf.com pull fuse tcu. I haven't done needed to do it myself in a few weeks but have done so numerous times.