Thrust into the spotlight after Jonny Castro Otto's second major knee injury in less than a year, 19-year-old Ait-Nouri has started the last six games.
The Frenchman – currently on loan from Angers, with Wolves having the option to buy him for £20million in the summer – has impressed Nuno as well.
"There is improvement, and he's playing," said Nuno.
"Regarding the circumstances we have in the squad, he's having game after game now.
"So, there's no better time for improvement than in the game itself.
"Of course, we work every day with all the players on the aspects that we feel need improvement.
"The defensive part of Rayan is one of those. So, the focus is there. He's been doing well."
Ait-Nouri is one of three Wolves players with buy options attached to their loans – the others being midfielder Vitinha at £18m, and striker Willian Jose at £22m.
There is scope to lower the price for each of those players should the club wish to pursue permanent deals, though.
Ait-Nouri has figured the most of the trio, making 19 appearances in the Premier League – and 14 as a starter. He has also chipped in with one goal and one assist.
Nuno, meanwhile, has also taken the time to praise teenage centre forward Fabio Silva after a bright display against Brighton.
The 18-year-old – signed for a club-record £35million last summer – set up Adama Traore's equaliser in Sunday's 2-1 victory, for what was his second assist in gold and black.
He has also four goals to his name this season, and Nuno is hoping for at least one more from him over the final three games of 2020/21.
"It was good. It was more or less like the West Brom game, against big centre-halves that don't give you space," said Nuno.
"They're always on you, so it's hard. But Fabio is doing much better on that aspect of his game – much, much better.
"The way he drops and then tries to find the spaces, the physicality of the Premier League can only help him.
"It was good, but he should score. We always want our strikers to score and we'll keep pushing for that alongside Willian. I think we have good options now."