Unfortunately, that's not a quick mash. The jeans, belt, pouches, and vest are all a single mesh. They can't be separated in Nifskope. A person would have to use Blender (or something similar) to literally cut them apart. If all you were wanting was the vest, the shirt underneath it would also need to be cut out. The belt and its pouches would likewise need to be "skinned" off the jeans and have their back sides re-built. There's also the issue of the outfit being a game asset. I think we're not actually supposed to do that.