I've never had any .esp with my NMC texture packs...Then again, my computer has never gotten along with NMM. I just used FOMM.
Anyway, it's the first one. Merge the NMC Directory into the New Vegas data folder. And yes, you want to overwrite (Thank god for the "Yes to All" button).
These textures should show up regardless of if you have an .esp enabled.
I've never tried the second route where you would have a data NMC directory. Don't know of anyone that has either. I would avoid the second option for now, just because I'm not familiar with it. If you want to do it that way, I'd wait for someone here to give you a hand.
let me know how it goes.
