In my opinion, there are only 3 teams that can beat the Lakers using small ball: OKC, the Heat, and Denver.

The Lakers should have an efficient half-court offense with Steve Nash at the helm.
The Lakers should have an efficient half-court defense with Dwight Howard bailing out his teammates.

The Lakers’ only vulnerability is their age – their only starter under age 30 is Dwight, who is a center who can’t be expected to stop many fast-breaks. If those 3 teams get out and RUN, they can wear down the older and top-heavy (I’m still not sold on the Lakers’ bench) Lakers. If they try to beat them in the half-court….the Lakers are a difficult matchup, to put it mildly.