NWScript:

//Written By James A Beggs
//This script is intended to be placed in some event
//to make a creature go sit down at the nearest unoccupied
//chair.
//It was inserted at the end of a dialogue after
//a PC is done talking to them.
//note that a few changes need to be made, depending
//on your module, as noted below in comments.
void main()
{
    int nIAmSitting=0;
    int iCounter=1;
    int iMaxChairs=6; //put whatever the max # chairs you have
    string sChair="ChairTagName"; //put chair tag name here
    object oCurrentChairCheck;
    object SittingCritter;
    ActionWait(10.0)
    while (!nIAmSitting)
    {
        oCurrentChairCheck = GetNearestObjectByTag(sChair, OBJECT_SELF, iCounter);
        SittingCritter = GetSittingCreature(oCurrentChairCheck);
        if (SittingCritter!=OBJECT_INVALID )
        {
            iCounter++;
            if (iCounter > iMaxChairs)
            {
                iCounter=1;
            }
            ActionWait(10.0);
        }
        else
        {
            ActionSit(oCurrentChairCheck);
            nIAmSitting=1;
        }
    }
}