powwow vs talk over

powwow is a noun but talk over is not a noun.

Word	Noun	Adjective	Verb	Adverb
powwow	Yes	No	Yes	No
talk over	No	No	Yes	No

As verbs, talk over is a hypernym of powwow; that is, talk over is a word with a broader meaning than powwow:

powwow: hold a powwow, talk, conference or meeting
talk over: speak with others about (something); talk (something) over in detail; have a discussion

Other hypernyms of powwow include discuss, hash out.

powwow (noun)	talk over (noun)
(informal) a quick private conference
a council of or with Native Americans

powwow (verb)	talk over (verb)
hold a powwow, talk, conference or meeting	speak with others about (something); talk (something) over in detail; have a discussion