The ornamental design for a portablearcherystand, as shown and described.
FIG. 1 is a front elevational view of a portable archery stand showing my new design;
FIG. 2 is a left side elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a right side elevational view thereof;
FIG. 5 is a right side elevational view thereof, shown in an alternate position;
FIG. 6 is a top plan view thereof;
FIG. 7 is a top plan view thereof, shown in an alternate position;
FIG. 8 is a bottom view; and,
FIG. 9 is a front and right side perspective view thereof, with the broken-line disclosure of a bow being for illustrative purposes only and forms no part of the claimed design.