Albert Barnes Commentary 2 Kings 23:30

"And his servants carried him in a chariot dead from Megiddo, and brought him to Jerusalem, and buried him in his own sepulchre. And the people of the land took Jehoahaz the son of Josiah, and anointed him, and made him king in his father`s stead." — 2 Kings 23:30 (ASV)

Dead - It appears from a comparison of this passage with the cross-reference in 2 Chronicles that Josiah was not actually killed in the battle.

Jehoahaz - Or Shallum, as noted in the margin. He may have taken the name of Jehoahaz (“the Lord possesses”) on his accession. He was not the eldest son of Josiah (see the note on 2 Kings 23:36). The mention of “anointing” here favors the view that there was some irregularity in the succession (see the note on 1 Kings 1:34).