It sure seems to be her, but she is just sitting there waiting for her cues. She doesn't have any real reactions to what he is saying, except those that she rehearsed, obviously.
This clip will go down as the worst speech in the history of American politics. Hillary tapes this address for a union convention. Someone must have told her that union guys like tough talk. https://www.youtube.com/watch?v=ZtLznfIDEzI