The ornamental design for a chisel holder, as shown and described.
FIG. 1 shows a right side view of a chisel holder, the left side view being a mirror image of the right side view.
FIG. 2 shows a front view of the chisel holder of FIG. 1.
FIG. 3 shows a top view of the chisel holder of FIG. 1.
FIG. 4 shows a front right isometric view of the chisel holder of FIG. 1, a front left isometric view being a mirror image of the front right isometric view of FIG. 4.
FIG. 5 shows a rear right isometric view of the chisel holder of FIG. 1, a rear left isometric view being a mirror image of the rear right isometric view of FIG. 5.
FIG. 6 shows another front right isometric view of the chisel holder of FIG. 1, a front left isometric view being a mirror image of the front right isometric view of FIG. 6; and,
FIG. 7 shows another front right isometric view of the chisel holder of FIG. 1, a front left isometric view being a mirror image of the front right isometric view of FIG. 7.
The broken lines form no part of the claimed design.