Season 3 was really good although I'm not sure I liked it quite as much as the first two, but still really good all the same.
I agree with so many comments on this season finale that I've seen in this thread.
It would appear that Gus knows, or suspects, Nacho for what has gone on. I wouldn't doubt in the least that Mike gave him a heads up as to what is happening but I also wouldn't be surprised if he simply picked up on something being wrong by the way Nacho was acting during the entire incident. The fact that he so calmly picked up the pills, while his boss is possibly dying, just so he could make sure he had them? It probably set off a glaring red flag for a guy like Gus. Either way it's pretty clear he knows and is going to see this as either an asset or a problem.
I don't know if Nacho is the same one that Saul is referring to in Breaking Bad but something tells me, gut feeling, that it's not. I don't know where they go from here with Nacho. I do believe this attack is going to be the one that puts Hector into the state in which we see him in through out all of Breaking Bad.
The reason Gus saves him is so glaringly simple for anyone who watched BB. Gus wants Hector to suffer for the way Hector treated his family when he first game into this business. There is no doubt that Gus didn't want Hector to go out so easily. This could also be why Gus could eventually see this as a problem with Nacho because he'll be pissed that Nacho almost took him out before Gus could be the one to do so. It's obvious (From BB) that punishing, and ultimately being the end, of Hector was the plan for Gus all along. It is awesome work though that they added this in due to the fact that those of us who loved BB know that Hector, ultimately, kills Gus (With the help of Walt).
I don't see Kim going into any Breaking Bad sort of situation. I do believe that this is the catalyst for her becoming all in with Jimmy that will ultimately lead to Jimmy hurting her, as the last person he has left, and it will be the final piece that is broken before Jimmy goes full Saul Goodman. I agree with the others that the speech by Chuck will be what starts sending him down that path where he ultimately hurts Kim. He will realize, next season, that Kim is the only person left that matters to him and that he can't be who he really is as long as he's got her to think about. So he'll ultimately ruin the relationship for his own personal gains later.
And you saw a small glimpse of just how terrible he can be, as Saul, with the way he played that poor old lady. Getting all her friends to hate her just to get his money but as we all saw he was still too much Jimmy, and not enough Saul, to where he had to fix it.
Chuck will be dead. Or at best fighting for his life when the new season starts and it will begin the end of Jimmy. The speech from Chuck, Chuck's death, everything will finally crash down onto Jimmy and force him to where he's always been headed anyway. Which, in the end, sort of makes Chuck completely right (Even if he is a big part of why Jimmy is that way) because in the end Jimmy is always going to burn every single bridge in his life to get things the way he wants them regardless of what it takes, or who it tramples on.
Right now Jimmy still has a heart, and it causes him to try and fix his mistakes, but by the end of next season he won't have that heart anymore. He'll be full blown Saul Goodman.
I was bummed the season ended with no Mike in it. He's one of my absolute favorite characters from either show.