2 Kings 23:29-30 and 2 Chronicles 35:23-24 appear to disagree on where King Josiah died -- Megiddo or Jerusalem.

Read carefully, the two accounts are consistent, not contradictory. 2 Kings 23:29-30 has Pharaoh Neco kill Josiah at a fatal encounter at Megiddo, then his servants carry him dead in a chariot from Megiddo to Jerusalem for burial. 2 Chronicles 35:23-24 supplies more circumstantial detail: Josiah is wounded by archers at Megiddo, tells his servants he is badly wounded, is moved to a second chariot, and dies -- either en route or upon arrival -- before being brought to Jerusalem for burial and mourning. Both texts place the fatal wounding at Megiddo and the burial at Jerusalem; Chronicles simply supplies additional detail clarifying the moment of death without contradicting Kings's terse summary that he was 'carried dead' to Jerusalem. Even taken at its most literal, 2 Chron 35:24 is fully compatible with a mortally wounded king dying during or at the end of the journey from Megiddo -- Kings never specifies the precise moment of expiration versus the location of the mortal wounding, so these are not competing claims about a single simple fact but a terse summary (Kings) and a fuller narrative (Chronicles) of the same connected sequence.

This is a good example of a 'contradiction' evaporating on close reading of the actual text without elaborate harmonization -- Chronicles' additional narrative detail supplementing Kings's summary is exactly the relationship expected between a terse royal-annals-style history and a more richly narrated theological history drawing on shared and additional source material.