Why is he called Pharaoh Necho?
Radak citing Targum Yonasan: Pharaoh the lame.
When was this Nevu'ah?
Radak: First he prophesized about Melech Mitzrayim's punishment outside his land. He came to Nehar Peras in Karkemish, which Melech Ashur and Melech Aram captured, like it says "ha'Lo k'Charkemish Kalno" (Yeshayah 10:9). Pharaoh Necho went there in the days of Yoshiyah and made a siege until the fourth year of Yehoyakim. Nebuchadnetzar came against him, and this Nevu'ah was said about him, and afterwards about Eretz Mitzrayim, that Nebuchadnetzar will conquer it.
Why does it say "bi'Shnas ha'Revi'is", and not b'Shanah?
Radak: It is normal that [Shanah] has the Semichus form when it is next to a number. The same applies to "bi'Shnas Shalosh l'Malcho" (Esther 1:3) and similar verses.
