Welcome to NICO!
Have you checked for any loose connections?
Unfortunately I'm not all too well versed in your vehicle, but can offer an option for you. Here at NICO, we have Factory Service Manuals available free to members. For some reason we don't seem to have the FSM for the 2015, but we do have the 2016 FSM. The wiring will be the same between the two, so it should suffice.
The rear camera is in the AV section. Here's the direct link to the Intro page for the FSM.
Nissan Note Model E12 Series