I have major doubts about the Orthodoxy of Catholic Chaldean Christology, because their approach appears to mirror that of the position taken by Nestorius.
Here is a summary of the Nestorian and Catholic Chaldean positions:
(1) Nestorius confessed that Christ is two essences (ousia), two subsistences (hypostaseis), and one person (prosopon).
(2) The Chaldean Catholics confess that Christ is two essences (kyane), two subsistences (qnome), and one person (parsopo).
Now, here is a summary of the Orthodox position, based upon the Councils of Ephesus, Chalcedon, and Constantinople II:
(3) The Orthodox confess that Christ is two essences (ousia), one subsistence (hypostasis), and one person (prosopon).
Finally, here is a summary of the Maronite Catholic position, which is important because the Maronites use the same terminology as the Catholic Chaldeans, but the Maronite formulation is clearly Orthodox:
(4) The Maronites confess that Christ is two essences (kyone), one subsistence (qnomo), and one person (parsopo).
Taking into account the foregoing information, the Catholic Chaldean position on Christology - for all intents and purposes - looks like the position of Nestorius; so whether or not the Chaldeans "venerate" Nestorius as a saint is really not that important, but what is important is the fact that the Christological doctrine of the Chaldeans does not appear to be Orthodox, because it diverges from the teaching of the Councils of Ephesus, Chalcedon, and Constantinople II.