FIG. 1 is a perspective illustration, from the front and right side, of a first embodiment of a nasal mask according to our design;

FIG. 2 is a top view thereof;

FIG. 3 is a bottom view thereof;

FIG. 4 is a right side view thereof, with the left side view being a mirror image thereof;

FIG. 5 is a front view thereof; and,

FIG. 6 is a rear view thereof.

Where included, broken lines showing environment or structure are for illustrative purposes only and form no part of the claimed design.