The hosts scored the only goal of a tense and cagey encounter after 83 minutes, as Callum Hudson-Odoi fired in at the near post to beat Ederson.
Earlier in the game, Nico himself came close to the opener, crashing a long-range strike onto the outside of the post.
Further efforts from Bernardo Silva, Kevin De Bruyne and Mateo Kovacic failed to hit the target as City fell four points behind Forest in the league table.
“Well yeah, it was a really tough match, we knew it was going to be hard,” said Nico in a post-match interview with CityTV.
MATCH REPORT: NOTTINGHAM FOREST 1-0 CITY
“We had our chances. We were much better than them in the first half. Second half I think it was a more open game. In the last minutes when you lose, it isn’t easy.
“Yeah I think apart from the goal I can’t remember another clear chance for them. That means we did a really good job defensively.
“At the end they wanted to keep the result 0-0 and they knew they would have a chance on the counter, or a corner, that’s why they’re third in the league and in a Champions League spot.
“It’s tough, it’s tough to accept it. But we have to keep working.”
The January arrival also spoke about his strike that struck the post and reiterated the importance of qualifying for next season’s Champions League.
Watch the entire interview via the video at the top of the page.
