I claim the ornamental design for a chair, as shown and described.
FIG. 1 is an upper perspective view of a chair;
FIG. 2 is a front plan view of the design shown in FIG. 1;
FIG. 3 is a back plan view of the design shown in FIG. 1;
FIG. 4 is a right side plan view of the design shown in FIG. 1;
FIG. 5 is a left side plan view of the design shown in FIG. 1;
FIG. 6 is a top plan view of the design shown in FIG. 1; and,
FIG. 7 is a bottom plan view of the design shown in FIG. 1.
The broken lines in the figures are for the purpose of illustrating portions of the chair, which form no part of the claimed design. The shade lines shown represent surface shading and not surface ornamentation, color, or material type.