nitrogen narcosis vs narcosis

nitrogen narcosis and narcosis both are nouns.

Word	Noun	Adjective	Verb	Adverb
nitrogen narcosis	Yes	No	No	No
narcosis	Yes	No	No	No

As nouns, narcosis is a hypernym of nitrogen narcosis; that is, narcosis is a word with a broader meaning than nitrogen narcosis:

nitrogen narcosis: confused or stuporous state caused by high levels of dissolved nitrogen in the blood
narcosis: unconsciousness induced by narcotics or anesthesia

nitrogen narcosis (noun)	narcosis (noun)
confused or stuporous state caused by high levels of dissolved nitrogen in the blood	unconsciousness induced by narcotics or anesthesia