Do you know for certain that the 9260 you purchased on Amazon is:
1. New or used
2. Genuine Intel or knockoff
3, Undamaged and known to be good.
Provide an image of the labeling on the 9260.
Also, you mention "Has anyone replaced a 3165 adapter with a 8260?". Are you looking at that as an alternative as well?
But, what you really want to ask is if this is possible on your NUC5PGHY.
) Package says that the 9260 is New
2) Have no idea if it is Genuine or Knockoff
3) Package says that it is New but have no way to verify if it works or is recognised in another device.
I attached pictures of the shielded package, actual adapter, and the Amazon site where it was purchased.
The 8260 reference was a typo and should have said 9260.