Technical Nestorianism and quasi-Incarnational Mariology

>But why am I so favored, that the mother of my Lord should come to me? [Luke 1:43, NIV] A secondary question in the Chalcedonian/Nestorian debate was whether it was more fitting to refer to Mary as the Theotokos (God-Bearer) or the Christotokos (Christ-Bearer). The passage from Luke just quoted seems to suggest a third option: Mary as the Kyriotokos, or Lord-Bearer. Of course, if being the Lord is tantamount to being God, this resolves to a defense of the Theotokos description. Now, rather later, one of the saints spoke of Mary in terms of a [quasi-Incarnation of the Third Person of the Trinity](https://saintmaximiliankolbe.com/who-are-you-o-immaculate-conception/) . My question is: does Nestorianism, ironically, give us a technical avenue for parsing this quasi-Incarnational thesis? What I mean is: modulo Nestorianism, might we say that whereas Christ was one person with two natures, Mary was two persons with two natures? It is specifically "by the power of the Holy Spirit" (c.f. Matthew 1:18) that the strict Incarnation proper was brought about; if Mary was the quasi-Incarnate Spirit, would such a Nestorian stature of hers be the very thing that "allowed" the Spirit to effect the strict Incarnation, through her? (Objection I anticipate: the Spirit could have effected this even if Mary were not the Spirit's own quasi-Incarnate estate. At any rate, though, the question of whether and how Mary had to be sufficiently sinless, to serve as the vessel of the Second Person of the Trinity, seems caught up in this other question.)