I'd be interested if a player could simplify it and answer your question well. Personally I think this is a very difficult question to answer well because there are a lot of different lines and ideas.
For the very simple version, white gets two bishops and black gets faster development / better pawn structure. In some lines the structure gives the same ideas as a queen's gambit. But others it's totally different. e.g. sometimes you see Nc6 with the pawn still on c7, sometimes white is playing f3 or g3, and of course many lines have white's c pawns doubled.
Nimzo-Indian pawn structures
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See thats the thing with the Nimzo Indian, there are a ton of pawn structures for both sides! Ive learned the basic from some old mastering the nimzoindian book by Soltis I think, but I have yet to play through Winning Middlegames by Sokolov that has a huge number of games featuring the pawn structures. There are like 6-8 basic structures that can be transitioned into, and many more advanced ones. Its a very pawn heavy opening.
What are some typical pawn structures you might see in a typical Nimzo-Indian game? What are the ideas for both sides (but especially interested in the ideas for Black) in those pawn structures?