Export/Import tools between Blender and the Nif format, using Bodyslide/Outfit Studio's Nifly layer. Works with official Blender versions 3.0-4.2. Can handle nifs for Skyrim LE, Skyrim SE, Fallout 4, and Fallout 76, Fallout New Vegas, and Fallout 3.
Windows only.
Full documentation in the wiki.
Features
Background
Outfit Studio has working export/import for a bunch of the Bethesda games. I'm a modder and I've been using the niftools scripts for years, but I've started modding for Fallout 4 and there's no direct support for that at all.
BS/OS has separated much of their code to deal with nif files into a separate library, nifly. I've used this library and some additional OS code as the core of an export/import addon for Blender.
My interest is primarily Skyrim, Skyrim SE, and Fallout 4 so I'll be focusing on supporting those games.
Status
Import/Export of most nifs is complete works well.
Import/Export of animations is currently under development.
Import/Export of Skyrim collisions is complete except for MOPP collisions. Those may never happen. Fallout 4 collisions are not implemented but there's a tool that ships with Fallout to help with that. Check the Collisions page of the wiki (https://github.com/BadDogSkyrim/PyNifly/wiki/Collisions) for more.