We'd like to think it's Nicole Kidman's acting that has theatergoers scrambling for tickets to The Blue Room, the actress' Dec. 13 Broadway debut. After all, she does get to show off several different accents while playing five different women in 10 sexually charged vignettes. But get real. The reason the 111-performance run is nearly sold out is Kidman's much-publicized onstage nudity. Actually, only Kidman's backside will be visible to most of the audience, and then only for a few moments in one scene toward the end. But if you're one of the lucky few sitting way down front by the far right wall of the Cort Theatre, or in the right-hand box seats and some ticket buyers have been asking you'll probably catch a fleeting glimpse of Nicole's bare upper torso. Of course, if Kidman's talents don't do anything for you, you can always sit back and take a gander at her costar, the handsome British stage vet Iain Glen: Him you can see do the full monty from any seat in the house.