Wigan were the better side in the opening 45 minutes and Emerson Boyce had a wonderful opportunity to hand his side the lead in the 18th minute, but the Wigan captain sent his free header wide from just six yards.
Callum McManaman and McClean continued to torment the Forest back four, but couldn't find an opener as the game is still goalless at the break.
It took until after the break for Forest to register any shot of note, when Henri Lansbury went close with a 20-yard effort.
However, Wigan maintained their superiority and would have gone ahead through Delort in the 53rd minute were it not for a good save by Karl Darlow.
McClean then came within inches of putting Wigan ahead with a snapshot from eight yards which shaved the outside of the post on its way out, before Michail Antonio headed wide from six yards at the other end as the game sparked into life.
Lansbury came close again with 15 minutes remaining but Wigan held on to restrict Forest to just a point.