The ornamental design for a decorativeelement for watch, as shown and described.
FIG. 1 is a front elevational view of a decorative element for watch showing my new design;
FIG. 2 is a rear elevational view thereof;
FIG. 3 is a left side elevational view thereof;
FIG. 4 is a right side elevational view thereof;
FIG. 5 is a top plan view thereof;
FIG. 6 is a bottom plan view thereof; and,
FIG. 7 is a right front perspective view thereof.
The watch depicted by broken lines in the drawings has been shown for the purpose of illustrating environment that forms no part of the claimed design.