The Frenchman also believes that next season will be more competitive than last year.
City finished last season in second place after a disappointing 2015 saw them fall away in the Premier League title race, with Chelsea ending up as clear winners.
They were also knocked out of both the FA Cup and Capital One Cup, and the Champions League by Barcelona. That poor season has led to many suggesting that there needs to be a major overhaul of the squad at the Etihad, and Nasri is expecting investment this summer.
"The club is going to invest, I think, in new players," he said.
"Who we need is a question for the manager but if we want to be competitive in every competition - and if we want to take a step forward in the Champions League - I think we need to strengthen in every area a little bit.”
Indeed, City have already started to make their moves in the transfer market having agreed a deal for Fulham youngster Patrick Roberts, according to The Mirror, while they have also had a second bid turned down for Liverpool’s Raheem Sterling, per BBC Sport.
They are not the only side looking to improve, though, with Manchester United expected to be one of the busiest sides, Liverpool having already secured three signings, and the likes of Chelsea and Arsenal unlikely to sit on their laurels.
And the Frenchman believes next year’s title scrap will be much more competitive than last season.
"The league is going to be really competitive,” he added.
“Manchester United are going to be there, Arsenal had a great season with another trophy and they were close, Liverpool want to buy players as well. I think it’s going to be really interesting.”