1999 Chevy Astro Lock Actuator

I am trying to replace the lock actuator on the passenger side door. I was able to remove the door's interior "skin" and have located the lock actuator. I can see that it's attached to a bracket which is attached to the door's interior by two screws that face out and are secured by two washer type nuts that I cannot remove. I can't grab hold of them. If I could remove them then I could remove the actuator and replace it. Do I need a special tool to do this or is there some trick I don't know about?

Thanks for your help.