The 48-year-old, who returned to the City Ground to take charge in February, guided Forest to four wins and a draw in their five matches during the month, a run which has put them in the play-off positions.
George Boyd is the Championship player of the month for March after producing some impressive displays following his loan switch from Peterborough to Hull City on February 21.
The 27-year-old netted four goals in his five matches for the Tigers during the month - including two on his home debut against Birmingham - and also made his first appearance for Scotland in the 2-0 defeat to Serbia.
Leyton Orient boss Russell Slade is the League One manager of the month after taking the London side into the race for the play-off positions with a run of four wins, two draws and one defeat in their seven matches in March.
Bournemouth striker Brett Pitman, 25, claimed the player award in League One after continuing his fine form since returning to the Cherries from Bristol City in December with five goals in six games during March.
Plymouth completed the double in League Two with John Sheridan named manager of the month and midfielder Jason Banton the player of the month.
Argyle dragged themselves out of the relegation zone during March with four wins and a draw from their six matches, their only defeat coming at leaders Gillingham.
Banton, 19, who is on loan from Crystal Palace, scored three goals in those six games.