I just got a used 2013 Leaf yesterday and this worked for me:
1. Turn on Nav screen by pushing the Car Start button (No need to step on brakes).
2. Once screen has loaded, press these buttons in sequence:
Map/Voice button 3 times, then
Radio power button 2 times, then
Map/Voice button once.
3. Go to Confirmation/Adj and choose "User Data Initialisation"
I got the procedure from Youtube: https://youtu.be/yW-AMNqzQqU