Morgan Rogers and Donyell Malen had Villa 2-0 ahead before Jota Silva set up a nervy finish by scoring for Forest.
Nuno lamented afterwards, “It was probably one of the matches where we created more chances. We are disappointed not only with the chances we created but didn’t score, but also with the way we started the game.
“We didn’t start so good. We were much better in the second half but the feeling is one of disappointment.
“We tried to make adjustments (at half-time) to help the players feel more comfortable on the pitch. In the first half, we were not able to control or to dominate. Villa broke us over and over again.
“At half-time, we tried to adjust. It worked out in terms of how the players performed in the second half.”
He also said, “If you look at the second half, you cannot say we were tired because we performed. I don’t think it is the big issue. It was more about the individual duels where normally we are stronger, but we were not so strong in the first half.
“This is the game. I should be fair with what happened and if I say something it would not be fair.”
Nuno admits the absence of injured striker Chris Wood also is affecting them.
“It was the same shape as we finished against (Manchester) United, with different personnel. The idea was to have an extra body in the last line that could close the gaps.
“We had Nico (Dominguez) on the right side to create overload when he comes inside. Many things that we tried.
“At the same time, not having a reference man up top meant the way we pressed and controlled was not the same. A lot of things went into our thinking.”