I'd say Nix was a part of Whaley's development so Nix deserves credit for beginning the talent overhaul of the Bills at the same time grooming our next GM. Whaley deserves a lot of credit working his way up.
http://www.sbnation.com/nfl/2013/5/14/4328444/doug-whaley-bills-general-manger-buddy-nix
Now Whaley has come into his own and is very well respected. We're lucky to have one of the young great minds in the NFL.