Hi m8, Thanks for the +rep.
Nanites are dropped mostly in underground as far as I know, I looted a few Improved Nanites and Adjusted Nanites on the Oratan Miners... There is a map regarding the mobs here:
http://imgur.com/a/XA1ZY Wombana and Oratan as well as Badgers is what I have hunted, Wombana is lower level and easy to kill, some of the Oratan are really huge and requires a medic (top left corner of underground) but if you go to Oratan Miner Low/mid which is on the top left, but one step to the right you can solo them with a medic using S10 if you have an armor like gremlin or Viceroy.
Happy hunting and hof big!
Edgewise