Whom did Nebuchadnezzar appoint over the people left behind in Judah?

Answer: Gedaliah son of Ahikam

Nebuchadnezzar appointed Gedaliah son of Ahikam, the son of Shaphan, over the people who remained in Judah.

“Nebuchadnezzar king of Babylon appointed Gedaliah son of Ahikam, the son of Shaphan, over the people he had left behind in the land of Judah.”— 2 Kings 25:22 (BSB)