What is "be'Hancheil Elyon Goyim" referring to?
Rashi: Refer to 32:7:3:1. 'When Hashem distributed their portions to those who angered him, He drowned and swamped them'.
Targum Yonasan. Da'as Zekenim, Hadar Zekenim: 'When Hashem divided the world among the nations that descended from the sons of No'ach'.
What is "be'Hafrido B'nei Adam" referring to?
Rashi: It is referring to when Hashem scattered the Dor Haflagah. 1
Targum Yonasan: It is referring to when He separated the scripts and the languages of the people of the generation of the Haflagah'.
Da'as Zekenim, Hadar Zekenim, Rosh: Each person went to his [own] place.
What is the meaning of "Yatzeiv Gevulos Amim le'Mispar B'nei Yisrael"?
Rashi: When Hashem scattered the Dor Haflagah, He could have destroyed them from the world. He did not. Rather, He kept them, and set up the seventy nations 1 (because of the seventy B'nei Yisrael that were destined to come from Shem 2 - and) because of the seventy souls who went down to Egypt'.
Rashbam: The Torah (in Bereishis Perek 10) lists seventy descendants of Noach, from which come the seventy nations, but it] specifies the borders only of Cana'an, because it is destined to be given to Yisrael. Cana'an and his eleven sons numbered twelve, corresponding to the twelve tribes of Yisrael. 3
Da'as Zekenim, Hadar Zekenim, Rosh: Hashem chose an inheritance for 12 Shevatim of Yisrael before they were born! He gave Eretz Yisrael to Kena'an, who were slaves of Shem, so they could not protest when we took their land. 4 Cana'an had 12 sons, like the Shevatim. The Torah lists 11, but it says "v'Achar Nafotzu Mishpechos ha'Kena'ani" (Bereishis 10:18). I.e. one of the families split, and the Prizi was added; he was not mentioned among Kena'an's sons.
Targum Yonasan: Which He did by drawing lots with the seventy angels who would ultimately govern them - who accompanied Him when He went down to inspect the city that the people were building. Ramban: Because every nation has a guardian angel that governs it - See Devarim 4:1, except for Yisrael, who fell to Hashem's lot, which explains the Midrash - that the image of Ya'akov is engraved underneath the Kisei ha'Kavod.
See Sifsei Chachamim.
Hadar Zekenim: Because what a slave acquires, it belongs to his master.