chain of mountains vs Sierra Madre Oriental

chain of mountains and Sierra Madre Oriental both are nouns.

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

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