MagicStrange

I was having the same issue so what I did was take the texture from the Virtual Install folder that NMM creates and dropped it in the DATA>Textures folder (didnt override anything) then they showed up right away just remember if you uninstall the mod in NMM you have to go into your data folder to do it as well (manually) and if you replaced an existing texture you may have to verify the download on steam again to get the default one back.