I add the raspberry with a touchscreen installed on the dash. It's not replacing the nissan's lcd. From what I search it's not possible when you have the NAV option. So I just follow this web site : https://github.com/opencardev/crankshaft/wiki/Getting-started-with-Crankshaft
Everything works great but wanted to have wifi tethering and now many problem using android auto. With the usb cable, it was good. It's like having a second screen from the phone but on the raspberry, with limited option (call, msg, gps, music)
I'll take a picture of my setup.
It's good but you cannot run leafspy on it. So, i'm actually trying something else the have all the same feature of a phone but with leaf spy.
Hope it clarify your question.