My first suggestion is MAKE the dealer fix it if you're still under warranty.
If you're not under warranty, read through the last 5 pages of this thread.
There are part numbers that myself and others have used/bought for replacements that have seemed to fix the problem.
Just a few days ago there was a member that found another Nissan switch that didn't have any issues, but also fit the Armada. @Bravosser
got a part number?
There was also mention of a TSB that required a computer re-flash. It's not really a huge problem, just annoying until you get it figured out.
The dealer not being able to figure it out would not be acceptable to me. I would escalate that to Nissan USA.