I want to learn how to use nifscope properly to make armor mashups for Skyrim. I've used it for both FNV & FO3, but my knowledge if it is still largely at the 'noob' level (i.e. I have the enthusiasm and sometimes things work, sometimes they don't and I have no idea why). The process I used for Fallout armors does not seem to work with Skyrim in game.

Can anyone recommend a tutorial that would help? The ones I've seen largely cover nifscoping models exported from blender / 3DS and don't seem to cover what I'm looking for.

what would you like to know?

nifskope is a program that you need to just play with to understand. It basically lays out a nif file in text format. once you understand what does what, then its pretty easy to use. Alot of the info in the nif is unusable, or never used; so while it looks big, there really isn't much to it.

Iirc the tutorials i looked at were at the nifskope site

They have a wiki: http://niftools.sourceforge.net/wiki/NifSkope