We claim, the ornamental design for a display screen or portion thereof with icon, as shown and described.
FIG. 1 is a front view of a display screen or portion thereof with icon showing our new design in a first embodiment;
FIG. 2 is a front view thereof in a second embodiment; and,
FIG. 3 is another front view of the design shown in FIG. 1, shown on a device.
The dashed broken lines illustrating a device in FIG. 3 are for environmental purposes only and form no part of the claimed design. The dash-dot broken lines indicate a boundary and form no part of the claimed design.