So I have a common exterior wall with a shower. I plan to do the normal waterproofing on that wall (which I assume will prevent moisture from condensing). However due to stud locations and a HVAC duct, I believe I might need to put a DUK Liner shower niche installed in that common exterior wall. I have 1.5" XPS outside and 1/2" sheathing with what will likely be 1.0-1.5" batt between the sheathing and duk liner in the cavity. With it all sealed from moisture, any issues with this? I plan to run membrain/intelloplus on the rest of the house.

Unless you will have people showering for many hours of each day, I would not expect this to be a problem. If you want to determine what the moisture accumulation rate will be inside the wall assembly during the high humidity shower period, you could exercise our building assembly moisture analysis software:

Borst Building Assembly Moisture Analysis Software

I avoided shower niches on my exterior shower walls.