Chaos erupted in a New Mexico courtroom when a slain woman's family attacked her suspected killer ... and the wild brawl is all on video.

The crazy scene went down Friday in Albuquerque when alleged murderer Alexander Ortiz went before a judge.

Ortiz is accused of killing his ex-girlfriend, Alianna Farfan ... and new video shows the moment Farfan's uncle, Carlos Lucero, hops over the courtroom gate and attacks Ortiz.

Fists are flying and Lucero takes his niece's alleged killer to the ground.

Another man rushes in to get some licks in on Ortiz ... and you also see Ortiz's father, Joeray Ortiz, rush in from the opposite side of the gallery to defend his son from his dual attackers, kicking one of them in the face.

The brawl continues for about a minute before sheriff's deputies arrive and break up the fight.

After the melee, Lucero reportedly told police the fight "was worth every moment" because "he killed my niece like a coward."

The uncle and his tag-team partner, Pete Ysasi, were arrested and charged with felonies.