Elliot Anderson and Chris Wood had Forest 2-0 ahead inside the opening 16 minutes. The hosts didn't reply until on 87 minutes through Richarlison, though Nuno admitted afterwards they had to dig deep to keep Tottenham out.
He said afterwards: "I think it was a big improvement. I think we reacted well from the previous game. There was a clear intention to bounce back and the boys did well.
"We have a clear way to play and when we found ourselves in our identity. We control really well the game in the first half. We had goals, but also Tottenham created chances in the second half and we had to hold on to what we had.
"I don't believe it impacts us, if we play before or after (our rivals), The way we approach it is game by game.
"I think we've been able this season to compete well and fight for every ball. The boys did it.
"We have a big week ahead of us. We want to recover the players and we can enjoy this.
"If you look back at the first half Tottenham created a lot of problems for us in wide areas. We had Matz (Sels) at a high level keep us in the game. You have to remember we are playing quality players."
"Result was fortunate for us"
On their defending from deep, Nuno admits Spurs forced their hand.
He continued: "There is no other way. Tottenham put us against the ropes so it is about defending and holding on to the result.
"We started the game well. We created danger with good combinations. We wanted to go more offensive in the second half, try to be more dangerous and have more of the ball.
"When you have something it is about getting through it, especially in these moments of the season when there is fatigue, not only physical but mental, anxiety, all these things made the team go back a bit. Credit to Tottenham. They created so many chances against us and we were fortunate to get away with the result.
"We were controlling the game but Tottenham were having lots of crosses and space in the wide areas, so it (half time change) was about having an extra man and squeezing a bit more. You have one less man to press in midfield but you then have one more in the box."
"Sels has been huge for us"
Nuno was eager to highlight the performance of Sels, who was outstanding in the second-half for the visitors between their posts.
"Matz has been huge for us all season. He kept us in the game so we are delighted," said Nuno.
"Our fans have been fantastic for us. Today they gave us an extra run, not only here but also at the City Ground. We cannot thank them enough
"We have a big week ahead of us. We have to prepare well then go to Wembley and enjoy. You don't get these moments often, especially in this league when we are fighting for something nobody expected."