Colloquial term for North Koreans, similar to Chicoms (Chinese Communists). I'm not what the modern connotation is, in my mind it's a little suspect but not really offensive compared to the typical race based terms used in other conflicts.

Derogatory slang for North Koreans[1]

Though not commonly used; though it does pop-up from time-to-time[2]

[1] https://www.urbandictionary.com/define.php?term=Norks

[2] https://www.nationalreview.com/the-feed/korean-war-ii-watch-...

It's a reference to the Dear Leader's chest

In the context, almost certainly North Koreans.