Strange smell in cabin was diagnosed by the dealer as a EVAP leak and needing replacement. I cannot seem to find much after searching the forums here and public Internet. Is ripping out the entire dash the only way?

Is it possible a full core replacement isn't needed? AC still blows cold..just smell at start up in cabin.

 

See the thread "Being told HVAC Box needs replacement". The evaporator core is in this HVAC box. Unfortunately the whole box gets replaced, and yes, they have to pull out the whole dashboard to get to it. The HVAC box is about 900 dollars, but with labor, can be almost 2K. You can get a strange smell when it starts to leak. Mine had a weird smell for about two weeks and the AC just quit blowing cold air, and unfortunately in my case, this was an HVAC box just replaced less than a year and half ago and only drove the car a little over 4K before it failed. The parts and labor warranty from Nissan is only 1-year, and Nissan Consumer Affairs will not budge on that. Now on the passenger side foot well, as your sitting in the seat, there is a plastic lower piece that will pop out next to your left foot. You can pop that out and get up in the footwell with a flashlight and see into the evaporator core to see if it's leaking. You'll see a green dye, it maybe small now and AC is still cold, but it will eventually fail and you'll get only warm air. Unfortunately not a cheap fix unless you have an extended warranty.

Here is a video of a 2018 Nissan Maxima, what it looks like to get the HVAC box. It's the same on other Maxima's 2016 and newer:

 

Mine is leaking as well and JUST found this guy that does it without removing the whole dash!! Some bending and getting dirty but it works!

 

JoeinGA - Just looked at the video. May be doable. I know I had another friend with the same issue and many local shops woudn't mess with it based on it's location. If it can be done for cheaper price with a warranty, I'd say go for it for anyone that needs it replaced.