1) Pressure and contain Aaron Rodgers
Rodgers doesn't have the mobility of a Tim Tebow, Michael Vick or Cam Newton, but he still has enough mobility to break free and pick up a first down or touchdown. The Packers' offensive line is without two tackles, so the Bears should be able to generate some pressure off the edge with Julius Peppers and Israel Idonije, but the defensive takes have to do their job too. It's not impossible - Rodgers has been sacked 36 times this year himself already.
2) Can Bowman Take Back His Starting Spot?
Remember, in week three last season, against these same Packers, Zackary Bowman was benched in favor of Tim Jennings. Bowman is a bit more of a ballhawk than Jennings, who is usually a bit more responsible in his coverages. Bowman gets a slight break in that he'll be matched against the Packers' #3 receiver with Greg Jennings out, but with the Packers' depth at receiver, that isn't saying much.
3) Stick with the defense
For whatever reason, historically the Bears' Cover 2 has given the Packers and Aaron Rodgers fits. Then Week 3 happened. Whether that effectiveness is due to the Packers getting conservative with a lead or the actual defense is its own debate, but the defense is an opportunity defense. Wth the offense as it is, the defense must take advantage of whatever opportunities it gets to take the ball back or force a punt. The defense has to continue to step it up on third down and force errant throws. If not, it'll be a long game.