Question: What Persian general took advantage of Nasr ibn Sayyar being preoccupied with a civil war? 
Sentence (from "Nasr ibn Sayyar"): In 746 Nasr was driven from his capital by Ibn Surayj and Juday' al-Kirmani, but returned after the latter fell out among themselves, resulting in Ibn Surayj's death.
Relevant evidence: No