Its been ages since I played NWN1+2. I can tell AoO happened automatically but I am not sure if you could have more than one.

In Pathfinder Kingmaker there is a feat that allows you to have more than one AoO per round. (combat relexes).
WotR has it too, plus a mystic feat to get more AoO.
It makes sense to use this feat:
- When standing close to an archer you get an AoO for every shot they make unless they have a feat to avoid this.
- Several of your chars have outflank and/or seize the moment. When somebody makes a crit against an enemy, all other chars get an AoO against that enemy. If the AoO is a crit it can lead to a long chain of attacks.
Should the enemy still be alive after this, the next char can get a crit with the regular attack, starting a new crit chain.

But DnD 5E has different rules ( I am not an expert, please correct me when I am wrong)
- Shooting while being close to an enemy gives disadvantage, not AoO
- You have only one reaction and AoO are not the only possible reaction.

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