The title of the article is misleading, since JGL didn't "not take Chris Nolan's advice". If you read JGL's comments, he said that he appreciated what Nolan said--and in fact, JGL's response implies that he actually did take the advice. Nolan did not tell him not to act and direct in the same movie--he said that he should really think about it. And JGL's response to that was "Totally valid perspective! Completely valid. I happened to go the other way and still do it, but a very valid question and I'm glad he asked it. Most people probably wouldn't want to ask me that and I'm glad he did." Very different from "not taking the advice".