I claim the ornamental design for a combined nose and mouth guard, as shown and described.
FIG. 1 is a front elevation of a combined nose and mouth guard showing my new design;
FIG. 2 is a left side elevation view thereof;
FIG. 3 is a right side elevation view thereof;
FIG. 4 is a top plan view thereof;
FIG. 5 is a rear elevation view thereof; and,
FIG. 6 is a bottom plan view thereof.
The phantom lines in the figures are intended only to aid in the understanding of the claimed design, are for illustration purposes only showing an article upon which the claimed design may be associated or applied, and form no part of the claimed design.