Nahi attacked the victim before the melee spilled into the corridor of the ground floor wing.
The victim was on his back when Nahi stabbed him multiple times about the head and top half of his torso.
"The victim attempted to defend himself by placing his hands up to protect his face, which had little effect," the summary says.
The "frenzied attack" lasted for approximately two minutes and only stopped when Corrections staff restrained Nahi.
While Nahi was being taken away, he shouted, "I'll get you, you f***. You'll still be here when I get back".
The victim was hospitalised with multiple serious stab wounds to his head and face, and defensive wounds to his hands.
Nahi pleaded guilty to wounding with intent to cause grievous bodily harm.
He will be sentenced on February 17.