John Carter is a war-weary, former military captain who's inexplicably transported to the mysterious and exotic planet of Barsoom (Mars) and reluctantly becomes embroiled in an epic conflict. It's a world on the brink of collapse, and Carter rediscovers his humanity when he realizes the survival of Barsoom and its people rests in his hands.
John is seen taking a leak through the bars of his cell at the beginning,his genitals are not visible. It wa clearly meant as a means to disrespect his captors.
Not technically a "nude scene" but we do get a VERY brief glimpse of the main character's naked butt as the aliens are bathing him. It's not sexualized or a closeup.