We claim the ornamental design for a chair shield assembly, substantially as shown and described.
FIG. 1 is a front perspective view of a chair shield assembly showing our new design;
FIG. 2 is a rear perspective view thereof;
FIG. 3 is rear elevational view thereof;
FIG. 4 is a front elevational view thereof;
FIG. 5 is a right side elevational view thereof;
FIG. 6 is a left side elevational view thereof; and,
FIG. 7 is a top plan view thereof.
The dotted line showings in the drawings of the chair are for the purpose of illustrating environmental structure and form no part of the claimed design.