Answer:

OTOE

Answer	Crossword Clue
OTOE	Nebraska native
OTOE	Oklahoma tribesman
OTOE	Siouan language speaker

OTOE	Amerind
OTOE	Siouan Indian
OTOE	Siouan-speaker
OTOE	Plains Indian
OTOE	Crossword Indian
OTOE	Native Nebraskan
OTOE	Western Indian
OTOE	Siouan tribesman

OTOE	Nebraska county
OTOE	Siouan tribe
OTOE	Nebraska Indian
OTOE	Nebraska City's county
OTOE	County in Nebraska
OTOE	Oklahoma Indians
OTOE	Tribe from Nebraska
OTOE	Oklahoma tribe

OTOE	Siouan speaker
OTOE	Tribe paired with the Missouria
OTOE	Sioux tribe
OTOE	Pawnee neighbor
OTOE	...-Missouria (Indian tribe)
OTOE	Oklahoma native
OTOE	Siouan-speaking native
OTOE	Early Nebraskan

OTOE	Nebraska county named for a tribe
OTOE	Oklahoma Indian
OTOE	Western native
OTOE	Early Missouri River basin dweller
OTOE	Early Midwesterner
OTOE	Midwest native
OTOE	Nebraska tribe
OTOE	Onetime tribe of the Winnebago nation

OTOE	Pawnee ally
OTOE	Tribe related to the Iowa and Missouri
OTOE	Chiwere speaker
OTOE	Native Oklahoman
OTOE	Plains native