The 40-year-old, formerly assistant to Jose Mourinho at Real Madrid, has signed a contract until 2016 to replace Tony Mowbray on Teesside.
Former Forest defender Kieron Freeman, meanwhile, has returned to the city to sign for Notts County on loan from Derby.
Steve McClaren's arrival at Pride Park has pushed the 21-year-old down the pecking order in recent weeks.
Source: Forest MAD
Source: FOOTYMAD
