Is there such a thing as a chronic nightmare disorder?

PTSD? Some people may have a chronic prsd , and night mares r usually part of the symptoms. There r medication that can help.
Technically, no. It's most likely what people call night terrors, or it's flash backs to traumas that appear in ptsd poeple's dreams as if occuring again. There is no official diagnosis of chronic nightmare disorder just night terror disorder - chronic nightmares causing awakening in the middle of the night with no memory of doing so. Commonly "flash backs" are understood as ptsd memories come back to life again.
Nightmares. As a sleep disorder and trauma expert I have had many patients who have had chronic nightmares for many decades. We were able to stop them! Check on my book No More Nightmares-How to Use Planned Dream Intervention to End Nightmares. Taught to over 35,000 people world-wide, I also teach this extremely successful skill over VTC and could teach you via HealthTap.