The Pathfinder HVAC control unit
will not fit in the head unit space on the OEM bezel. Based on the pictures you've seen above, the original bezels were modified so that the HVAC control unit would fit. It's not difficult to do, but I'd think twice before doing so. I too tried to modify my OEM bezel based off of those pics posted above. After several tries I was successful, however it also opened a whole other can of worms.
I'm not sure which year you have, but on my 2002 QX4 there is a bar, which is probably apart of the frame, that is hidden right behind the dash. It will prohibit you from fitting a normal 7" In Dash unit properly.
Long story short, I would order a bezel off of eBay that's from a Pathfinder with a navi unit. This method requires no modifying of any parts and a more simple installation.
With all that said, I do agree that the method above looks better, which is why I did it also...