Forest progressed to the last four of the competition for the first time since 1991 and the coach was thrilled as captain Ryan Yates stepped up to fire in the winning kick.
Nuno, who sat in the dugout through the shootout, said: "It means a lot for all of us and especially for him to take the last penalty to send us to Wembley. Remarkable.
"I’m too nervous. It’s a moment of anxiety. And superstition. I just prefer to sit down.
"It means a lot, it’s a huge moment for our club and on our journey. It’s a huge competition, the FA Cup. We are delighted."
Forest have won three penalty shootouts in a row to reach the semi-finals and Nuno praised goalkeeper Matz Sels and those who stepped up to score for his side.
Nuno said: "Good goalkeeping but also good shooting. The third time and it’s the first penalty we missed in all the shootouts.
"It’s credit to the players. And of course fantastic goalkeeping."
Forest's FA Cup run comes during an impressive Premier League season that has seen them push for Champions League qualification and Yates is delighted that the supporters will get a day out at Wembley next month.
He said: "It's been an incredible season.
"We have achieved nothing yet but to send [our fans] to Wembley again - we know how special it was last time, getting promoted.
"It will be a special day and I am so pleased for the supporters and overall I think we deserved it."