Without beating around the bush: Unoptimized content due to inexperience.
The inventory images make up about 180MB of that. The texture files are also larger than they need to be for something this ancient. Some models are needlessly complicated. The longsword mod suffers the same issue.
It's less egregious in the later mods. Since all my weapon mods rely on the same texture files, I suggest installing this and the longsword one first, so a later mod's files overwrite those.
In any case, it's on the list to be fixed, but that list will be tackled once I've gone through all weapons, shields and helmets at least once.

i don't mean to be rude but how come the filesize is so large?
i am not sure almost 300mb for neverwinter nights weapon parts is ideal

lovely work!

It does not. It comes with its own textures, which should be installed by Steam. If all else fails, you can find these files on the Vault as well.

Cant seem to get this to work. Does it not work with Beamdogs weapon textures?

Thanks for the response. I'm playing on Windows.
Most likely there is some sort of file conflict caused by the mess got in my Override, I tried deleting other files that would be related to Greatsword replacement but it didn't seem to work for me (or I just missed some).

It should work simply by subscribing from Steam. There could be some issues with the following:
Do you play on linux? It might be an issue with the model names if that's the case.
If you have other overrides for the original greatswords, there is likely a conflict.
The Steam subscription also does not appear in the Toolset, only in the game.
Downloading from the Vault and manually placing the files into the override map should work both for the game and the toolset, but you have to put them directly into the override map and not in a subfolder.

Thanks for the upload. How to get it to work though? Is specific campaign module required? I tried keepign it subscribed and even tossing all files into Documents\Neverwinter Nights\override but the models don't seem to show up for greatswords