Nahuatl vs Native American

Nahuatl and Native American both are nouns.

Word	Noun	Adjective	Verb	Adverb
Nahuatl	Yes	No	No	No
Native American	Yes	Yes	No	No

As nouns, Native American is a hypernym of Nahuatl; that is, Native American is a word with a broader meaning than Nahuatl:

Nahuatl: a member of any of various Indian peoples of central Mexico
Native American: any member of the peoples living in North or South America before the Europeans arrived

Other hypernyms of Nahuatl include Amerindian.

Nahuatl (noun)	Native American (noun)
the Uto-Aztecan language spoken by the Nahuatl	any member of the peoples living in North or South America before the Europeans arrived
a member of any of various Indian peoples of central Mexico

Nahuatl (adjective)	Native American (adjective)
	of or pertaining to Native Americans or their culture or languages