Start Documenting...now!
Write down names, dates, places, witnesses, content of conversations.
After a few of these nasty encounters, talk to the GM (if you think he'll give you a fair hearing) and see what he can do. Maybe he'll move you out of the department and make you News Ops Manager or something else untouchable by him.
In the worst case senario, and if legal in your state, secretly record conversations with the ND. This is last resort stuff. Have a "talk" with him regarding your future. If he calls you too old or some other reason for poor treatment, keep two copies of that tape and take it to a lawyer for redress. But, under no circumstances do anything at work but perfect behavior. This is only to be done if you absolutely know the ax is falling!
Too bad. I was in your position a few months ago and he ended up leaving first and now life is better with the new ND.