More info on Mike Nolan. I'm sold. From the GB Press-Gazzette.
Nolan also has appeal because though he prefers to run a 3-4 defense, he’s also worked in the 4-3 and mixed that in extensively as coach of the 49ers. In his first season with San Francisco, the 49ers ran mostly a 4-3 and gradually evolved into primarily a 3-4 defense over his three-plus seasons with the team.
McCarthy also might prefer a slower transition to the 3-4, because the Packers’ roster is built to play a 4-3, and switching to primarily a 3-4 in one offseason could be difficult and require major changes in personnel.“He’s good now. He’s smart,” said the scout who’s familiar with Nolan. “He can run 3-4, 4-3, he knows it all. It depends on what personnel you have. He’ll do whatever, morph to whatever. He’ll use your players to their strengths. He’s smart that way.”