I really don't see either Nash or AI as being overrated. They are having terrific seasons. Nash is certainly playing like a potential MVP candidate, leading a team with no legitimate big to the fourth best record in the NBA.
As for AI, maybe he was not perceived as a team player earlier in his career, but now he has certainly learned to play in control and take smart shots (personally I think he has a far better shot selection than Kobe Bryant who jacks up three pointers from 25 feet away). The truth of the matter is, whether you like AI or not, by the time he finishes his career he will likely be the all time leader in steals and within the top 3 or 4 in total points (not to mention third in ppg). The numbers alone obviously merit some name recognition. More importantly though, twenty years down the line he will likely be looked at as the best offensive little guy in the history of the NBA and easily one of the toughest and fastest. Beleive it or not, I am no fan of AI's, but let's be honest here - Iverson perhaps has the most unique style of play in the NBA. When is the next time there will be a six foot tall man who can score 30+ points and command double teams? He may not be the perfect ball player, but easily one of the best in the game today and well deserving of his fanbase and name recognition.