I don't get the review of Nick Nurse's corner play. I see no possibility that his behaviors are not framed in one of 3 options: as a coach box violation, as a coach entering the court or simply an unsportsmanlike conduct.

1) Coach box violation.
The rules say he is supposed to be between his side substitution line and the baseline. That is the coach's box.
Rule 12, section V, item C - indicates that the penalty for coach's box violation is a technical foul.
2) Unsportmanlike tatics: entering the field without permission.
Rule 12, section V, item D defines that unsportsmanlike tatics result in a technical foul. Then, it lists examples of unsportsmanlike tatics, Among them, there is a mention to "A coach entering onto the court without permission of an official".
If we consider the line NOT part of the court, one could even argue that Nick Nurse is not IN the court, but in anyway, his feet is BEHIND THE BASELINE.
3) Unsportmanlike tatics in general.
Let's forget the little rule details. Nick Nurse, who was wearing a grey t-shirt that resembles celtic's green when in quick motion, positioned himself like a player with a body posture typical to players in the corner waiting for the ball. Wasn't it unsportsmanlike enoguh?
The same Rule 12, section V, item D presents only EXAMPLES of what could be considerer unsportmanlike tatics. By using the expression "such as" as listing possibilities, it leaves space for other actions to be ruled as unsportsmanlike.