The nom de guerre Pol Pot didn't appear in the New York Times until August 1976, which was after things calmed down in Cambodia. Which makes your assertion he was doing so at the time unlikely.
Vietnam invaded Cambodia and the US began arming Pol Pot and the Khmer Rouge in the late 1970s and 1980s, which again the Times covered, although slightly obliquely. Chomsky condemned the US arming Pol Pot and the Khmer Rouge.
Buzz off with your revisionism. Chomsky said the numerous reports of mass murder were a sea of lies. History has proven him dead wrong. He should have known better but was blinded by his ideology; all too eager to believe America was making it all up, and all too eager to believe leftists wouldn't commit such crimes.
This is what Chomsky wrote about Ponchaud's Cambodia book in June 1977
"Ponchaud’s book is serious and worth reading, as distinct from much of the commentary it has elicited. He gives a grisly account of what refugees have reported to him about the barbarity of their treatment at the hands of the Khmer Rouge."
So a book about the barbarity of treatment by the Khmer Rouge is "serious and worth reading". That is what Chomsky actually wrote back then if anyone is actually curious. Does not sound like what you claim he was saying.
He later did the exact same thing during the Bosnian war and the Srebrenica massacre in particular (where Chomsky among other things defended a publication called "Living Marxism" which published a completely made up article alleging Western media turned a a "refugee center" into a concentration camp including faking photos including that particular photo that looked like a KZ you might remember from that war. Chomsky has defended and assumed the position of LM on this into the 2010s).
Now you might say "surely he has come to his senses", except Chomsky went on to spread lies about the Sarin gas attacks in Syria.
To those who aren't aware, Noam Chomsky vehemently denied Pol Pot's mass murder of millions in Cambodia.