Fury: Congrats, kiddo.
Natasha: Yes, congratulate me— for lying, cheating, and stealing in order to succeed.
Fury: I prefer to think of it as “spying”, Natasha. And ya do good work.
Natasha: Don’t I always? Isn’t that why— in one form or another— there will always be a Black Widow?
This final scene points out that Natasha, for all her expertise, has some moral misgivings about the things she does. It’s not something she revels in, not really, not deep down.
Keep in mind the multiple meanings of the word good. I think what Fury means is that she’s very good at her job. That she’s the best there is at lying, cheating, stealing &c. But I don’t think that’s what Natasha’s responding to, here. She does good work. The greater good. And that’s why there will always be a Black Widow.
From Journey Into Mystery #519, Scott Lobdell and Randy Green.