Peter Diamond Is Not Qualified For Fed Board
Does the fact that he is now a co-recipient of the Nobel Economics price make him more qualified?
In short: no. Remember, this price was about problems in bringing together buyers and sellers in for example labor markets. This has really nothing to do with monetary policy, and so the arguments againt Diamond are still valid. This is similar to how Paul Krugman's previous largely valid research in the economics of trade doesn't make him a good macroeconomic analyst.
Of course, it is possible for an economist to be a good analyst in more than one subject. But the fact that someone is good in one specialized field of economics doesn't prove that this person is good in other fields as well.