nmos1v
This is the 1V device (gate/drain breakdown).
nmos2v
This is the 2V device (drain breakdown, need to verify if gate breakdown is 2V, sometimes it is not)
nmos3v
This is the 3V device (drain breakdown, need to verify if gate breakdown is 3V, sometimes it is not)
nmos1vcap
Nmos capacitor? Seems like it might be a moscap.
nmos1vhvt
1V device with threshold implant for high threshold voltage (reduces leakage).
nmos1vlvt
1V device, with threshold adjustment for a low threshold voltage (more leakage, but better headroom).
nmos1vn
Not sure about this one.