The ornamental design for a nursingblanket with back supporting pillow, as shown and described.
FIG. 1 is a front view for a nursing blanket with back supporting pillow showing my new design;
FIG. 2 is a right side view thereof;
FIG. 3 is a back view thereof;
FIG. 4 is a left view thereof;
FIG. 5 is a top view thereof;
FIG. 6 is a bottom view thereof;
FIG. 7 is a perspective view shown in an environment of use thereof; and,
FIG. 8 is a perspective view shown in an environment of use.
In FIGS. 7 and 8, the broken lines, showing portions the human form, a chair and stroller, illustrate the design in use and form no part of the claim. The remaining broken lines, shown throughout the views, represent the portions of the design, which form no part of the claim.