City won the Johnstone’s Paint Trophy at the national stadium while maintaining their push for promotion to the Championship with 14 points in their six league games.
Cotterill’s side beat Walsall at Wembley and also secured league victories against Leyton Orient, Crawley and Yeovil – all away from home – and Crewe Alexandra on their own ground, to stay top of the division.
Also nominated are Keith Hill, Lee Johnson and Dave Robertson.
Hill led Rochdale to five wins in their seven games to maintain their play-off push and Johnson turned Barnsley from relegation candidates to the fringes of the top six with 12 points from six games.
Robertson was installed as interim manager at Peterborough following Darren Ferguson’s sacking and has guided the team back towards the play-offs with four wins in six games which included three clean sheets.
Bristol City are also represented among the Player of the Month award nominees, with Aden Flint on the short list after scoring three goals to take his tally for the season to nine. The centre-back also contributed to three clean sheets in six games and scored the tone-setting opening goal at Wembley.
Also in the reckoning are Bradford City midfielder Billy Clarke, Rochdale striker Ian Henderson and Daniel Johnson of Preston North End.
Clarke was the Bantams playmaker behind James Hanson and Jon Stead in March, scoring twice and laying on several key passes.
Henderson helped himself to five goals from a wide attacking position for the Dale, while Johnson has contributed four game-changing strikes from central midfield as North End ramped up their automatic promotion bid.