What is the meaning of "Nikro Nikreisi"?
Radak: I came by chance. I did not intend to find him there. It is Makor Shalem (like an infinitive, with the initial Nun) from the Nif'al Binyan, like Nish'ol Nish'al" (20:28)
What is "Chaniso"?
Malbim: It is the sword through which he was stabbed.
Who are "Ba'alei ha'Parashim"?
Targum Yonasan: They are Mashrayas (camps, of soldiers on horses). Radak - he similarly translated "Ba'al Gad" (Yehoshua 11:17) as Meishar 1 Gad.
Radak: They are the leaders of the soldiers on horses, who are appointed over them.
Why does he say 'similarly'? The words have the same root letters, but there it is a place (the plain of Gad), like Rashi explained (there, and Bereishis 14:6)! (PF)