I've been watching Pacquiao for more than nine years, and he still hasn't proven to me that he has it upstairs to come back from behind. I still think he's a frontrunner. Nelson by decision.
Pacquiao by stoppage late in a war. Azumah had problems with people with a speed advantage over him (Mario Martinez, Sweet Pea, Villasana), and Pacquiao would have that advantage easy. B)
Pac seems to be the kind of guy that fights at such a fast pace that he overwhelms guys who are thinking fighters. This would probably give him a distinct advantage against guys like Tszyu, Lewis, or even Nelson and possibly even Floyd. As far as P4P goes.
Pacquiao isn't on the same level as Mayweather is. Why's everyone making such a big deal out of him beating two old super bantamweights?
I think Nelson might've beaten the less dimensional Pac of 126, but from the 3rd Morales fight onward, I think Pac had too much all-around speed and versatility for him.
I think Pac is generally a bad matchup for The Prof at any weight. Too much handspeed and power, and from odd angles. Difference being, at 126 its Pac by decision. At 130, I think Pac gets Nelson out of there late.