The ornamental design for a single element misting nozzle, as shown and described.
FIG. 1 is a top perspective view of the design of my single element misting nozzle.
FIG. 2 is a front elevational view thereof, in which back, left, and right elevational views are mirror images thereof.
FIG. 3 is a bottom axial plan view of the inventive design.
FIG. 4 is a top axial plan view thereof; and,
FIG. 5 is a view, similar to that of FIG. 2, however showing the position of the single element misting nozzle when positioned relative to a ceiling surface and water conduit which are shown in phantom forming no part of the claimed design.