The ornamental design for a nightlight, as shown and described.
FIG. 1 is a first perspective view of a night light showing the claimed new design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a left side elevational view thereof;
FIG. 5 is a right side elevational view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof; and,
FIG. 8 is a perspective view of a watchband attached to the night light when it is in use.
The broken lines shown in drawings are included for the purpose of illustrating portions of the night light and environmental structure, and form no part of the claimed design.