The Belgian – coming back into the side for Adama Traore as Nuno opted for a 3-5-2 formation – expertly found the bottom corner just after the hour mark.
In what was a big boost to Wolves' European ambitions and a bitter blow to the home side's survival hopes, Dendoncker was the star of the show.
And Nuno said: "I'm very, very happy for Leander. I'm happy for the team, but especially for Leander as he's a fantastic footballer and hard worker.
"He gives us so much. So, to have this moment is important for him – and important for us. And we keep on going – keep on going."
Dendoncker – who has also spent a large chunk of the season playing in defence – burst up from midfield, shifting the ball onto his left foot and driving it beyond the helpless Orjan Nyland.
Jonny Castro Otto did very well to hold the ball up and provide the assist, too.
Dendoncker has been such a useful option – whether in midfield or defence, or as a starter or substitute.
When asked if he sums up Wolves' spirit of always being ready, Nuno said: "It's all about that – always preparing yourself to compete.
"It's up to us to make decisions regarding the 11, the players that go in, but what's more important is how we prepare.
"It was a tough game and Villa created a lot of problems. It required running, second balls, and I'm very pleased with the performance of the team. Physically, we were very strong.
"The game required a different approach. Villa started the game well with their two strikers and a lot of people in the middle.
"We started well and we maintained the organisation through all the game.
"Even after we scored, the team stayed compact and really, really solid."
With the win, Wolves completed the double over Villa and made it three league wins in a row for the first time this term.
They have also now picked up 27 points on the road, but Nuno said: "We try not to make any difference between home and away. Now, football has changed.
"The main effect for the home team is their fans, so as long as you keep the same approach, it's almost like playing in a neutral venue."
The Wolves chief added: "We have a good week now to recover as it was a tough cycle – the third game in a week. We know what is in front of us.
"This week will require good recovery, to prepare us for the next challenge."