Nile monitors are scavengers. They do not actively hunt cats. However, if they see a dead one in the road or killed in some other manor, they will eat it. I am willing to bet that 90% of the cases/reports of Niles eating these larger mammals is them scavenging pretty killed food.
Agreed, more likely someone saw one eating road kill and just assumed the lizard did it.
Where are we going, and why am I in this handbasket?
Never argue with idiots. They will drag you down to their level and beat you with their experience.
Artificial intelligence is no match for natural stupidity.