When I think of the 3 main things Phoenix does on offense, I see Bibby being successful in all three aspects equal to Nash.
Leading the break:
Bibby, while not as quick as Nash, is very capable of running the break. His passing in the open floor is marvelous. 3 seasons back, with a healthy-pre-knee injury Webb, we had 4 guys who could run down the floor and finish at the hoop (Christie, Webber) or spot up outside (Stojakovic, Bibby).
Nash is in a similar situation with arguably better supporting players. Stoudemire and Marion play above the rim with the best of em and Joe Johnson and Quentin Richardson are both deep threats. Nash is a 40% 3 point shooter also. He can drain the three if all else fails on the break.
Pick-and-roll:
In Dallas, Nash and Dirk killed us with this play, over and over, night in and night out. Dirk sets the pick at the arc for Nash, if Bibby goes around the pick (which he always does) Nash has the option of spotting up, or dribble penetration to draw the double team. If Bibby switches onto Dirk, there is an instant mismatch, forcing a double team from Webber or Stojakovic and after 2 passes, Michael Finley has an open jumper or a drive to the basket. Nash runs the same plays in Phoenix, but is far more deadly because of the supporting cast. Stoudemire is growing into one heck of a smart basketball player. His jump shot gets more and more range as he gets more experience. Same pick play, which they also run with Marion, produces the same results. An open look for Nash, a mismatch with Stoudemire on a pg who forces a double, or open jump shots or drives from Marion, Johnson, or Q.
On the flipside, Bibby knows the 2 man game just as well. He was forced to learn it inside and out to counter the Stockton-Malone punch against Utah 3-4 seasons ago. He had to perfect the pick and roll with Webber to compete. If the defender goes under the pick, Bibby spots up or drives. Webber can spot up if both defenders chase Bibby. He can pass the ball to Peja if the rotation isn't quick enough or if Webber draws the double team. I have no doubt Bibby could be just as successful as Nash in the pick-and-roll in Phoenix.
Lastly.
Dribble Penetration:
What Bibby lacks in speed, he makes up for in dribble moves. We've all seen Bibby's patented hop-crossover and how can get to the basket. Bibby is one of the best pg at using his body and offarms to shield shot blockers away from his lay-up attempts. Defenses know this and have to counter by doubling Bibby in the paint, which allows him to find an open Kenny thomas, or Darius Songaila, Brad Miller for the open 18 footer. Even better, he finds Peja for 3.
These are just 3 basic basketball aspects where Bibby would easily equal Nash if surrounded by the athleticism and talent in Phoenix.
Phoenix is healthy. They have all played with each other all year and have perfected the run and gun style, which heavily favors athletic scorers. The Kings, because of all the trades and injuries, haven't had the practice time to build the cohesion and chemistry like the Suns have. That is the main reason we aren't as successful as Phoenix this year.
Bibby would flourish in Phoenix.