FIG. 1 is a perspective view of a first embodiment of a nasal mask showing the new design;

FIG. 2 is a side view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is other side view thereof;

FIG. 5 is a back view thereof;

FIG. 6 is a bottom view thereof; and

FIG. 7 is a top view;

FIG. 8 is a perspective view of a second embodiment of a nasal mask;

FIG. 9 is a side view thereof;

FIG. 10 is a front view thereof;

FIG. 11 is other side view thereof;

FIG. 12 is a back view thereof;

FIG. 13 is a bottom view thereof;

FIG. 14 is a top view;

FIG. 15 is a perspective view of a third embodiment of a nasal mask;

FIG. 16 is a side view thereof;

FIG. 17 is a front view thereof;

FIG. 18 is other side thereof;

FIG. 19 is a back view thereof;

FIG. 20 is a bottom view thereof; and,

FIG. 21 is a top view.

The portions of the Figures shown in phantom lines are not part of the claimed design but are for illustration only.