Sierra Madre Oriental vs chain of mountains

Sierra Madre Oriental and chain of mountains both are nouns.

Word	Noun	Adjective	Verb	Adverb
Sierra Madre Oriental	Yes	No	No	No
chain of mountains	Yes	No	No	No

Sierra Madre Oriental (noun)	chain of mountains (noun)
a mountain range in northeastern Mexico the runs parallel to the coastline of the Gulf of Mexico	a series of hills or mountains