Northwestern's offense came out extremely sharp in its opener this past Saturday producing 43 points and 517 yards against Maryland. 
Yes, Iowa's defense presents far more of a challenge. But the Wildcats' offense is much improved from a year ago with Indiana transfer Patrick Ramsey at QB. Ramsey has a pair of good running backs in Drake Anderson and Isaiah Bowser. Ramsey completed passes to seven different receivers. The Wildcats also have one of the better kickers in the Big Ten with Charlie Kuhbander. 
Iowa gave up 24 points to Purdue in a 24-20 opening-week loss to the Boilermakers last Saturday. Purdue played without its superstar wide receiver, Rondale Moore. Yet the Hawkeyes still struggled on pass defense.
The Hawkeyes have a good running back, too, in Tyler Goodson. Iowa's new QB, Spencer Petras, flashed at times. He connected with eight different receivers.
Both teams can move the ball on the ground. Ramsey and Petras are good enough passers to be able to take advantage of this by picking their spots and doing well off play-action.