Nevada law regarding arrest is given here. A private person can effect an arrest "For a public offense committed or attempted in the person’s presence" (as well as felonies not in the person’s presence). Trespassing is a misdemeanor: the guard, acting as agent of the property owner has given notice to leave the property, the order was ignored, and the person was lawfully arrested. Reasonable force can be used to effect an arrest (e.g. holding a resistant person by the arms) – I assume that is what you mean by "attack".
Now the problem is that under NRS 171.174,
If the arrest is without a warrant, the prisoner shall without
unnecessary delay be taken before a municipal court or a justice of
the peace or other magistrate of the county wherein such an arrest was
made, and such court shall admit such person to bail, if the offense
is bailable, by taking security by way of recognizance for the
appearance of such prisoner before the court having jurisdiction of
such criminal offense.
and NRS 171.178
2. A private person making an arrest without a warrant shall deliver the arrested person without unnecessary delay to a peace officer.
Except as otherwise provided in subsections 5 and 6 and NRS 171.1772,
the peace officer shall take the arrested person without unnecessary
delay before the nearest available magistrate empowered to commit
persons charged with offenses against the laws of the State of Nevada.
There are three options for the security guard. One is to secure the criminal and deliver him to the police station. Another is to call the police to have the criminal taken (by the police) to court. Option 1 apparently was not taken, and option 2 failed because the police are not obligated to perform prisoner transfer services. Which brings us to the third option that the property-owner decides to give up on the arrest. All of this was done according to law, thus this is not false arrest.