1)
What is the meaning of "ha'Nosen Nekamos Li"?
1.
Rashi: He gives to me strength to take vengeance from my enemies.
2)
What is the meaning of "va'Yadber Amim"?
1.
Rashi #1: He killed. It is an expression of Dever (plague).
2.
Rashi #2: He led. The Targum of "va'Yinhag" (Shemos 3:1) is u'Devar. Also Menachem explained so. The same applies to "Yadber Amim Tachtenu" (47:4).
3)
What is the meaning of "Tachtai"?
1.
Rashi: In place of me. This is like it says "v'Eten Adam Tachtecha" (Yeshayah 43:4).