Of course Natasha would agree with Tony’s backfire. During the time she was spying on him for SHIELD, she had the chance to see every one of those aspects first-hand!

And to make it more hilarious, she’s probably agreeing to each word in a different and less flattering context from Tony’s, when we recall she also has her own list describing Tony (albeit -again- on less flattering terms: “Mr. Stark displays textbook… narcissism.”) on her report to Fury from Iron Man 2. She’s probably mentally smirking as how Tony is unknowingly confirming each and every description she made about him in his snark-back to Steve.