The ornamental design for a nozzle for a manually operated spray tank, as shown and described.
FIG. 1 is a perspective view of a new and ornamental design for a nozzle for a manually operated spray tank;
FIG. 2 is a first side elevation view thereof;
FIG. 3 is a second side elevation view thereof;
FIG. 4 is a front elevation view thereof;
FIG. 5 is a rear elevation view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof; and,
FIG. 8 is a perspective view thereof, shown with a spray tank wherein the spray tank and hose are shown in phantom lines for environmental purposes only and forming no part of the claimed design.