1)
What Goyim were put upon him?
1.
Rashi: "Va'Yishlach Hashem Bo Es Gedudei Kasdim v'Es Gedudei Aram v'Es Gedudei Mo'av v'Es Gedudei Bnei Amon" (Melachim II, 24:2). They gathered them against him (Targum Yonasan).
2)
Why does it say "va'Yifresu Alav Rishtam b'Shachtam Nispas"?
1.
Malbim: Yeho'achaz was caught in their pit without the net. He did not fight with Melech Mitzrayim. However, Yehoyakim rebelled and fought, and they needed to spread a net, siege and fortresses until he was caught.
