One of the interesting aspects of Nash's comments is that his natural modesty lets him set up the criteria for the comparison as "one on one". One of on one, there are maybe three dozen guys who are better than Nash. Maybe more.
What that doesn't do is describe how Nash's skill as a floor general, play maker, and decision maker elevates his game to MVP level. What is equally important is that no other "pass first" point guard has anything approaching his range and accuracy on his three point shooting nor his amazing mid range game.
But clear the floor and just have Marbury on Nash one on one, then Marbury's street game shines. But that doesn't make him the best.