The ornamental design for a chair, as shown and described.
FIG. 1 is a perspective view of a chair showing my new design;
FIG. 2 is a first side elevation view thereof;
FIG. 3 is a second side elevation view thereof;
FIG. 4 is a third side elevation view thereof;
FIG. 5 is a fourth side elevation view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof;
FIG. 8 is a representative perspective view of the chair showing an ottoman nesting within a concave curvature of the base of the chair;
FIG. 9 is a representative perspective view of the chair showing an ottoman adjacent thereto; and,
FIG. 10 is a representative perspective view of the chair adjacent showing another chair nesting within the concave curvature of the base of the chair and yet another chair adjacent another side of the chair.
The broken lines shown in the drawings are included for the purpose of illustrating portions of the chair and/or adjacent structure that form no part of the claimed design.