1)
What is "Sha'on"?
1.
Metzudas Tziyon: It is commotion.
2)
What is the meaning of "Nishpat"?
1.
Rashi: We will debate in judgment.
2.
Radak: It is as if He entered judgment with them, and punished them for their evil via handing them over to Melech Bavel.
3)
Why does it say "Riv la'Shem ba'Goyim Nishpat Hu l'Chol Basar ha'Resha'im"?
1.
Malbim: Hashem has a quarrel with all the Goyim in general, and a decisive judgment against all who sinned against Him. The Mishpat will determine who is Chayav Misah, and they will be handed over to the sword.
