Indian chieftain vs Indian chief

Indian chieftain and Indian chief both are nouns.

Word	Noun	Adjective	Verb	Adverb
Indian chieftain	Yes	No	No	No
Indian chief	Yes	No	No	No

As nouns, Indian chieftain and Indian chief are synonyms defined as:

Indian chieftain and Indian chief: the leader of a group of Native Americans

Indian chieftain (noun)	Indian chief (noun)
the leader of a group of Native Americans	the leader of a group of Native Americans