Luke 1:49: Mostly Syntax and Some Semantics

Greek (THGNT): ὅτι ἐποίησέν μοι μεγάλα ὁ δυνατός· καὶ ἅγιον τὸ ὄνομα αὐτοῦ·

Martin M. Culy, Mikeal C. Parsons, and Joshua J. Stigall (Baylor Greek Handbook for Luke, pages 43-44 ):

ὅτι. Introduces a causal clause.
ἐποίησέν. Aor act ind 3rd sg ποιέω. On the second accent, see
1:13 on ἡ δέησίς.
μοι. Dative of advantage. On the word order, see 1:2 on ἡμῖν.
μεγάλα. The anarthrous substantival adjective functions as the accusative direct object of ἐποίησέν.

ὁ δυνατός. Nominative subject of ἐποίησέν.
καὶ. It is unclear whether the conjunction introduces the second of three conjoined clauses that together form a compound ὅτι clause (which would require changing the period after δυνατός to a comma), or it serves to introduce a new main clause. Given the semantics of this clause, ἅγιον τὸ ὄνομα αὐτοῦ, it seems less likely that it is part of a large causal construction (thus the translation).
ἅγιον. Predicate adjective of a verbless equative clause.
τὸ ὄνομα. Nominative subject of a verbless equative clause.
αὐτοῦ. Possessive genitive.

Zerwick-Grosvenor: "ἐποίησέν aor. ποιέω. μεγάλα neut. pl. of μέγας. δυνατός powerful,
ὁ δυνατός the Almighty. καὶ co-ord. "and" instead of rel. prn "whose" sec.455epsilon."

Rogers and Rogers: "ἐποίησέν aor. ind. act. s. v. 25. μοι dat. sing. ἐγώ I. Dat. of
advantage, or personal interest."

Joseph Fitzmyer (Anchor Bible Gospel of Luke, page 367): "for he who is mighty. This is the second reason for Mary's praise. Literally, it runs, 'for the Mighty One' (ho dynatos), a title used of Yahweh in the LXX of Zeph 3:17; Ps 89:9. The name of God is no longer used; instead there is a title recalling his exalted power, by which he has done great things for Mary-given her both a child who will be the Savior, Lord, and Messiah and a chance to express her faith in him."

Louw-Nida 74.3: ὁ δυνατός: (derivative of δυνατόςb ‘able, can,’ 74.2; a title for God, literally ‘the one who is able’) one who is capable of doing anything - ‘the Mighty One, Mighty God, the Almighty.’ ὅτι ἐποίησέν μοι μεγάλα ὁ δυνατός ‘because the Mighty One has done great things for me’ Lk 1.49.

BDAG: δυνατός, ή, όν (Pind., Hdt.+; loanw. in rabb.). ① pert. to being capable or competent

ⓐ in general sense, able, capable, powerful of beings and their attributes, esp. political power or influence

α. of transcendent beings: God (Plut., Numa 65 [9, 2]; IG XII, 8, 74; ILydiaKP [s. δύναμις 5] no. 224 p. 117; Ps 23:8; 44:4, 6; Ps.-Phocyl. 54; EpArist 139; Just., D. 129, 1) D 10:4. God as ὁ δ. (Ps 119:4; Zeph 3:17) Lk 1:49. Of angelic beings Hs 9, 4, 1.

β. of humans: prominent people (Thu. 1, 89, 3; X., Cyr. 5, 4, 1; Polyb. 9, 23, 4; oft. LXX; Philo, Mos. 1, 49; Jos., Bell. 1, 242 Ἰουδαίων οἱ δυνατοί; Just., A I, 14, 4 δ. βασιλέων) Ac 25:5; 1 Cor 1:26; Rv 6:15 t.r. (Erasmian rdg.; s. RBorger, TRu 52, ’87, 57). Of pers. gener. (PsSol 5:3) δ. εἰμι I am empowered 2 Cor 12:10; 13:9; ἄνδρες λίαν καλοὶ καὶ δ. very handsome and powerful men Hs 9, 3, 1. Of women, fig. for virtues 9, 15, 3. Of faith w. ἰσχυρά Hm 9:10. Of the spirit 11:21.