I can create human figures with ‘rigable’ skeleton, either on Makehuman as an app or Mixamo as online tool
Can I rig (move parts of the skeleton)
Is that a question? If you want to know if you can use an RIG from a other app in Nomad to pose the characters, then no.
Working on a rigging / animation app
Not animation but rigging. I’m still torn between apps I can use only on PC and those I can use on Android Tablet. I usually go out with tablet only.
I use Mixama to create animation and the extract the positions to manipulate on Nomad
Try POSEIT.
It is an Android App.
See if that will do what you are looking for.