Is a violent physical reaction to nightmare similar sleep walking?

No, a violent physical reaction is typically associated with a disorder known as REM sleep behavior disorder (RBD), rather than sleep walking.

In REM sleep behaviour disorder, individuals physically act out their dreams, often with dramatic movements and vocalizations.

Sleepwalking, on the hand, involves walking or performing other complex behaviors while asleep, but usually does not involve the same level of physical violence or aggression as seen in RBD.