Just to clarify matters for some of you, the Assyrian church (which is in fact the last remnant of the original Church of Persia) is not considered Orthodox by the actual Eastern Orthodox Church. The Persian Church had fallen away by the end of the first millennium after succumbing to the Nestorian heresy. They have never recanted this heresy, which makes the current move to restore communion with them highly peculiar.
I don’t think the Assyrian Church can be said to be “Nestorian” now, even if it ever was.
In 1995 or so, its Patriarch Mar Dinkha and Pope John Paul II signed a declaration of common Christology, which was ratified by the Holy Synod of the Assyrian Church.
Furthermore, back in the 800’s or so, one of their theologians wrote this, which sounds like the definition of Chalcedon to me:
One is Christ the Son of God,
Worshiped by all in two natures;
In His Godhead begotten of the Father,
Without beginning before all time;
In His humanity born of Mary,
In the fullness of time, in a body united;
Neither His Godhead is of the nature of the mother,
Nor His humanity of the nature of the Father;
The natures are preserved in their Qnumas*,
In one person of one Sonship.
And as the Godhead is three substances in one nature,
Likewise the Sonship of the Son is in two natures, one person.
So the Holy Church has taught.