The ornamental design for a naildryer, as shown and described.
FIG. 1 is a top plan view of a nail dryer showing my design;
FIG. 2 is a bottom plan view thereof;
FIG. 3 is a left side view thereof;
FIG. 4 is a right side view thereof:
FIG. 5 is a rear elevation view thereof,
FIG. 6 is a front elevation view thereof;
FIG. 7 is a perspective view thereof; and,
FIG. 8 is another perspective view thereof.
The dashed or broken lines shown in the drawings depict portions of the nail dryer in which the design is embodied that form no part of the claimed design.