In a really unceremonious way I did this by simply pasting ShockHandRight.nif into my LightningClaw.nif. I really don't know much at all about meshes, had a comment on my mod page from SpcSpectre about a sparking Warhammer 40K Lightning Claw so...this is my attempt (so far) to try and make that happen in a way.
ShockHandRight.nif is found is Data\Meshes\Actors\CreateABot\CharacterAssets
LightningClaw.nif used to be RebarFist.nif (Puncturing Mod for the Power Fist).
The idea was to get a visible lightning effect on the weapon and it worked...sort of! The Player can Equip a Power Fist with a Lightning Claw Mod and get a cool sparkly weapon to punch stuff with.
(Click the spoiler for example of the effect)
BUT, when an NPC tries to wear a Power Fist with the Lightning Claw mod on it....they fade into invisibility. You can still target and talk etc. just can't see them. This is also not like the Chameleon "invisibility", more like disabled type invisibility. So I guess something in the ShockHandRight.nif (which is essentially an animated lightning ball) conflicts with NPCs in particular...but I don't know what.
Something I did try before, which resulted in a CTD when mousing over the mod in the Crafting Menu, was to copy the exact naming from ShockHandRight.nif to the one now stuffed inside my custom .nif. Whatever the reason, the ugly Copy/Paste Branch job I did only works when I don't mess with it further!
Any ideas as to why this would happen? I have to admit I'm rather stumped.