FIG. 1 is perspective view of the chair cushion showing my new design, it being understood that the broken line showing of the chair is for illustrative purposes only and forms no part of the claimed design;

FIG. 2 is a front elevationl view of the chair cushion as shown in FIG. 1;

FIG. 3 is a right side view of the chair cushion as shown in FIG. 1 with the left side being a mirror image of the right side;

FIG. 4 is a top plan view of the chair cushion as shown in FIG. 1;

FIG. 5 is a bottom view of the chair cushion as shown in FIG. 1; and,

FIG. 6 is a rear view of the chair cushion as shown in FIG. 1.