Rashi #1: All my good is from Him.

Rashi #2: "V'Chosi" is my calculation. This is like "Tachosu Al ha'Seh" (Shemos 12:4). Also Menachem explained so.

Radak: I have no other portion. Just like these people that their portion is gold and silver and pleasures of this world, Hashem is my portion. Manah, Chelek, Kos ¹ and Goral are all the same. The matter is repeated in different words. to strengthen it. In all my matters, He is my portion and my intent is for Him.

Malbim: I am not under the Ma'arachah and natural powers. Kos is the portion that a person prepared for himself via his preparation. Goral portions need not be equal. (a) Every person has a Chelek in Hashem due to his Nefesh, which is a 'part' of Hashem - Hashem Menas Chelki. (b) One can merit additional Kedushah via his preparation, according to his deeds - Hashem

Rashi, from Sifri (Re'eh 53): You put my hand on the good portion - "ha'Chayim veha'Maves Nasati Lefanecha