Nasri enjoyed a productive season with Manchester City, scoring seven goals and setting up just as many in his team's Premier League-winning campaign.
But he was left out of France's provisional 30-man squad for the World Cup, with suggestions Deschamps was worried Nasri could be a disruptive influence.
Vieira, head of City's elite development squad, said he was shocked by the decision.
"I played with Samir in the national team and I am still working with him at City," Vieira said at ITV's World Cup launch.
"We never heard nothing about him at City. I think in France sometimes they are not strong enough to deal with personalities.
"It's quite surprising because Deschamps has personality and experience."
France meet Switzerland, Ecuador and Honduras in a Group E which many would expect them to progress from.
Vieira said Deschamps simply should have selected the best players – including Nasri, who he feels deserved a spot.
"If you want to win the World Cup you need to select the best players," he said.
"And Samir, this year he has been fantastic. He did everything to go to the World Cup. He has been scoring goals, making assists.
"The way he has grown up is his influence on the group and the team. He is a positive lad, he has been working really hard and he is taking more responsibility on his shoulders.
"He has got personality, and a strong personality. He never had a problem with Manchester City."
