1)
What did they see?
1.
Rashi: They saw Hashem go out to fight those nations.
2.
Radak: They saw Hashem's wonders and mighty acts - "v'Nishpateti Ito b'Dever uv'Dam v'Geshem Shotef v'Avnei Elgabish Esh u'Gafris
2)
What is the meaning of "Nechpazu"?
1.
Rashi: This is like "uv'Fachazusam" (Yirmeyah 23:32; Rashi there - they were confounded).
2.
Malbim: They were frantic to flee.
