Hi answer is stupid. Knowing if you are in a one score or a two score game doesn't mean a thing. That is the wrong question. The right question is, which is easier to come back from a one score game or a 2 score game with 4 minutes left? Pretty easy. So if he made the 2 pointer that would put them down by 7. A 1 score game. If he missed it, they are down by 9 points, a 2 score game. If he kicked the PAT he is down 8 points still a 1 score game.
What if Atlanta scores a TD? If you are down 8 points, they go up on you 15 points. Still a 2 score game. (1 TD & PAT and 1 TD & 2 point conversion) If you are down 9 points though and they score a TD you are now down 16 points, still a 2 score game but that means you have to convert 2 2 pointers. The odds are not good. It is hard to convert 1 let alone 2.
The smart move is to kick the PAT and tie the game and then see what you can do in OT. Expecting to convert an onside kick is silly. That may never happen again in 20 more years. Both options are doable, but both options are not equal. The highest probability of success is going for the PAT and then getting a TD and trying a 2 pointer for the tie VS trying for the 2 pointer and expecting to convert an onside kick to have any shot at all.