It's fine. The NV assets come packed in .bsa files and some mods you download may come with .bsas of their own as well. As long as your Data folder looks like:
Data\meshes and not
Data\data\meshes you should be good to go.
The Archive Invalidation tool included in FOMM works well but if you have problems with missing textures, make sure that it did indeed edit all three of your ini files with the
Fallout - AI!.bsa listed under the Archive section.