Been having trouble packing things like NMC textures into BSAs. I know about the 2 gig limit, and proper naming structure.
I pack the Large NMC pack into two separate bsas:
"NMC - Textures.bsa"
and
"NMC - Textures2.bsa"
Then I make a dummy esp in the GECK and call it "NMC.esp"
Still, no matter what, nothing loads in-game. Curiously, in mod organizer, it shows that these bsas are overriding other mods and some of the official DLCs, but not the vanilla game. If I unpack all of Fallout 3's textures and override them with NMC textures, I can then repack everything into two bsas "Fallout - Textures.bsa" and Fallout - Textures2.bsa" and everything will show up in-game. There seems to be an issue with the dummy esp not forcing the textures to load.