Each of these players is considered one of the better guards in the NBA. Chris Paul is more of a scoring point guard while Steve Nash is known for his amazing ball handling and passing skills. It is hard to say which is better, but I think each has their own talents that differ from the other one.
Chris Paul is an ultra fast guy who can burn people off of the dribble. He has pure speed and can finish at the rim. Most guys also have to give him a step or two because of his speed. This allows him to get many open looks and drain some long three point shots as well. His passing is also good and moves the ball around to all the different players quite well.
Steve Nash uses more misdirection that pure speed and often has no look passes that amaze the fans. He can shoot very well in the mid range area and is very unusual with the way he moves making it very hard to guard him. He also can dribble in traffic and draw the defenders to him giving others good looks at the basket.
Overall I would say Nash is the better true point guard and Paul can score better. Each is an all star type player and each could be in the Hall of Fame someday. Comparing them is hard but you cannot go wrong with either guy. I would love for my team to have one of these awesome guards to run the show.
Below are a few sites that also talk about great athletes.