The ornamental design for a chainskirt, as shown and described.
FIG. 1 is a perspective view of a chain skirt showing my new design in the
position of use, the broken lines partially showing a torso skirt and belt
throughout the view being for illustrative purposes only and forming no
part of the claimed design;
FIG. 2 is a front view of the chain skirt shown in FIG. 1; and,