NIF is a popular file format used by 3D games such as Morrowind, Oblivion, Fallout 3, Civilization IV, and many more. The Blender NIF scripts enable you to read and write files that are compatible with these games in Blender.
This release fixes plenty of bugs, and has a few new features, including limiting bone influences in the weight squash script (helps detecting clipping), alpha channel display in the 3d view, Fallout 3 interpolator fixes, havok fixes, animation improvements, and experimental Empire Earth II import and export.
You can grab the latest version of the scripts here:
https://sourceforge.net/projects/niftools/files/blender_nif_scripts/
For more documentation and help with the scripts, visit the wiki or the forum:
http://niftools.sourceforge.net/wiki/Blender
http://niftools.sourceforge.net/forum