No hassle 😄

Whaat has provided us with another great plugin http://forums.sketchucation.com/viewtopic.php?f=323&t=23725&hilit=plugin to help with UV mapping.

It is a bit of fussing around, but apart from Blender, I am really not aware of any other (freeware) possibility of converting a .skp file into a .nif file.