He was of Valyrian origin, as the Targaryens were among the forty noble families in Old Valyria, and the ones who escaped the Doom, thanks to Daenys.

Source: https://gamerant.com/game-of-thrones-aegon-conquest-explained/

Nettles' lack of Valyrian features is remarked upon too often for it to be insignificant.

Source: https://collider.com/house-of-the-dragon-season-2-nettles-missing/

The Rhoynar was destroyed by the Valyrian Freehold some 1,000 years before the events of leading Nymeria to lead her people to safety and freedom.

Source: https://screenrant.com/game-thrones-spinoff-prequel-shows-upcoming-explained/