The ornamental design for a shoppingcartchildseatcover, as shown and described.
FIG. 1 is a plan view of the outer side of the shopping cart child seat cover showing my new design;
FIG. 2 is a plan view of the inner side thereof;
FIG. 3 is a perspective view of the shopping cart child seat cover thereof; the seat cover being in a folded state;
FIG. 4 is a perspective view of the shopping cart child seat cover, the seat cover being in unfolded state and shown in use;
FIG. 5 is a front view thereof; and,
FIG. 6 is another perspective view of FIG. 4.
The broken line showing of portions of the shopping cart child seat cover is included for the purpose of illustrating environmental structure and forms no part of the claimed design.