The Saints like to blitz. A lot. It's a core component of Gregg Williams' defense. His installation of exotic blitz looks for New Orleans in 2009 was a key component to their defense being a top 5 unit in the 2010 regular season. The constant application of pressure on the QB is rarely a bad thing, and if they don't know where it's coming from, it's even better.
So that's not a secret. The key is what the Bears will do to counteract it. There are two particular weapons that could come in very handy, and they showed textbook execution of one last week.
The Quick Curl and the Screen
Last week, the Saints weren't getting a whole lot of time in the Packers backfield, mainly because Rodgers didn't give them enough chance. The Saints defensive back played pretty far off their guy most of the night, and watching this video of Aaron Rodgers highlights shows you most of what you need to see. Rodgers abused the Saints with a very quick release, and guys who were effectively boxing out defensive backs, putting them in the only real position to catch the ball.(The other thing Rodgers was doing to them, effectively, was putting it on his receiver's back shoulder. I would not expect a ton of that from the Bears.)
The Bears, on the other hand, showed an other-worldly understanding of executing the screen pass. Watching this video of Bears highlights will show a great job by Cutler of drawing the blitz, and excellent work by the fullbacks, tight ends, and linemen of getting out in space to make blocks downfield for the running back.
Now, you can use both plays too much, and an overreliance will tip the Saints off pretty early. But used in the right situations, and it can definitely take advantage of a hurting Saints secondary.