Albert Barnes Commentary 2 Chronicles 17:7

"Also in the third year of his reign he sent his princes, even Ben-hail, and Obadiah, and Zechariah, and Nethanel, and Micaiah, to teach in the cities of Judah;" — 2 Chronicles 17:7 (ASV)

The princes were not sent as teachers themselves, but were given the responsibility of ensuring the people were taught. The actual teachers were the priests and Levites mentioned in 2 Chronicles 17:8.