These first two games of the season have pitted the Packers against what are projected as the best defense and offense in the NFL. They passed week 1 adequately enough, especially considering defenses are generally considered ahead of offenses early in the season. Last week's contest between the Falcons and Bears also may have lent more credence to that old axiom.
Tonight, it's the much maligned Packer defense vs. the Falcons record-setting offense. It's still early enough in the season that the defense may still be somewhat ahead of the offense. Then one also has to consider that this is an important home game for the Falcons and especially their fans. How much that will affect anything on the field of play is questionable - noise, lights in the eyes, unfamiliarity of the turf. But unless the Falcons have also practiced on this field often to get an edge, even if only slight, those factors should affect both teams about equally. After a few series any potential edge regarding those items is probably no longer a factor, anyway.
Perhaps last season's regular season game between these two teams is more relevant when it comes to anticipating tonight's outcome. Unless either team gets hit with strategically key injuries during this game, I would expect the competition to be much closer than it was for last season's playoff game. If both teams are healthy then a home field three point spread in favor of the Falcons is reasonable - maybe even another point or two added to that with the opening the new stadium being a possible outlier. If both Packer OTs can't play (or play well) because of injury/illness, or if they depart the game early then the spread should favor the Falcons by at least a touchdown - more if a third Packer O lineman were to fall in this game.
Here's the big unknown "IF" that could be proven or debunked tonight regardless of whether or not the Packer O line gets bit by injury: Is this defense capable of carrying the team to victory if problems befall the offense? We'll know better by the morning.