Nestorius was condemned, but there was no discussion of Nestorianism, no condemnation or even mention of Theodore of Mopsuestia. Theodoret had refused to condemn Nestorius for 20 years, and did so only with very bad grace at the end and with no conviction. It did not change his Theodorean Christology. Ibas had been busy spreading the writings of Theodore of Mopsuestia, and was not asked to condemn any of his ideas. Indeed we know that he was willing to condemn Nestorius for foolishness while also elevating Theodore of Mopsuestia as Teacher of the Church. Therefore his condemnation of Nestorius at Chalcedon means absolutely nothing. Theodoret also was willing to allow the use of the phrase 'Theotokos' because it was in common use, but he never meant by it what St Cyril meant by it.
After Chalcedon Theodoret was very clear that his Theodorean Christology had been preserved.
Although St Cyril was praised, in fact his Christology was rejected. St Dioscorus said no more than St Cyril had done. The fathers of the Council produced a Definition which used St Cyril's Christological terminology, but this was rejected by the Romans and they insisted that a Definition using the terminology of Leo of Rome and Theodore of Mopsuestia should be substituted.
It was a confusion - as the Fathers of the time recognised - because it left many things entirely ambigious. This is why staunch Chalcedonians could keep a feast of Nestorius, could continue to translate and distribute the works of Theodore of Mopsuestia, and could insist that the Christology of Theodore of Mopsuestia, Theodoret and Ibas was canonised at Chalcedon.
It is a matter of fact that Nestorius had been invited to attend Chalcedon but death prevented him. The Imperial aim was to restore the Church to the pre-431 position.
This in no way means that every bishop at Chalcedon was a Theodorean, but the Theodorean language and ideas were certainly given breathing space, which is why Constantinople 553 had to deal with them all over again. Indeed so ingrained were these ideas that most of the Western Church went into schism rather than accept their condemnation, and leaders of the Churches in the West were willing to be put into prison by the Emperor rather than condemn what they believed had been canonised at Chalcedon.