NKN is an acronym for Nice kid, nice. NKN is gaining popularity as internet slang, however; it stems from common street slang of individuals growing up , namely breakers (break-dancers), in the early 70's in NYC and other U.S. locations which brewed up the lifestyle and genre we now call Hip-Hop.
I don't buy the schmegegge about Morty sleeping with Moira.
His version of the story was pure schmegegge.
The whole schmegegge was made up to get Liz a little bit of attention.
Looking or experiencing something nice after witnessing something horrid like a disgusting gif or a disturbing video. Typically used as eye bleach are nice images of whatever makes the disturbed person happy.