the shapes property of Body is a list of nape.shape.Shape's, not MovieClip's, you should be adding the brickShape to the body's shapes list, not a Movieclip.
Nape itself has nothing to do with graphics, and its up to you each frame, to move the grapihc associated with a body to the correct position/rotation based on the physics object state.
What you can do, is store the movieclip in the userData field of the body so that you can access it easily later if necessary like:
body.userData.graphic = brickMovieClip;
then each frame you can update the graphic like:
var mc:MovieClip = body.userData.graphic;
mc.x = body.position.x;
mc.y = body.position.y;
mc.rotation = body.rotation * 180 / Math.PI;