Adam Clarke on 2 Kings 23:30

Dead from Megiddo - The word מת meth should here be considered as a participle, dying, for it is certain he was not dead: he was mortally wounded at Megiddo, was carried in a dying state to Jerusalem, and there he died and was buried. See 2Chr 35:24.

Herodotus, lib. i., c. 17, 18, 25, and lib. ii. 159, appears to refer to the same war which is here mentioned. He says that Nechoh, in the sixth year of his reign, went to attack the king of Assyria at Magdolum, gained a complete victory, and took Cadytis. Usher and others believe that Magdolum and Megiddo were the same place. The exact place of the battle seems to have been Hadadrimmon, in the valley of Megiddo, for there Zechariah tells us 2Kgs 12:11, was the great mourning for Josiah. Compare this with 2Chr 35:24, 2Chr 35:25.