chet is a nickname
like wolf is a nickname for the predator
its obv not its actualy name,who would get close to a alien to be able to name it and call it,it would destroy you
same goes for a predator
the crew called the predator wolf because how it stalked etc
they nicknamed the predalien chet...i dont know prob because they got bored calling it predalien all time eg
"can we get the predalien on site please!"
boring
"can we get chet on the site please!"
better
why make something simple awakared and easy