Chiarelli has the final say on who they pick but Benning makes most of the recommendations on who to draft.
Here's a description of Bennings job as AGM for the Bruins from NHL.com:
"In that position, he serves as an advisor to General Manager Peter Chiarelli on all matters pertaining to player evaluation, trades and free agent signings, in addition to assisting the General Manager in overseeing all individuals in their specific duties for the Bruins."
Player evaluation meaning he deals with the pro and amateur scouting. Chiarelli doesn't do everything himself.
Since becoming AGM in 2006 Jim Benning's draft record is as such:
Players who have played over 50 NHL games: (4)
Joe Coulbourne
Jordan Caron
Tyler Seguin
Dougie Hamilton
Here is a description of Fenton's job as AGM for Nashville from NHL.com:
"Now in his 16th season with the Predators, and his eighth as the club’s assistant general manager, Paul Fenton has been instrumental in bringing in many of Nashville’s core players, primarily through the draft, but also through trades and free agent signings."
Since becoming AGM in 2006 Paul Fenton's draft record is as such:
Players who have played over 50 NHL games: (10)
Nick Spaling
Jonathan Blum
Colin Wilson
Roman Josi
Anders Lindback
Gabriel Bourque
Mattias Ekholm
Craig Smith
Ryan Ellis
Seth Jones