We claim, the ornamental design for a display screen or portion thereof with icon, as shown and described.
FIG. 1 is a front view for a display screen or portion thereof with icon showing our new design; and,
FIG. 2 is the enlarged front view thereof, without broken lines for clarity of disclosure.
The dash-dot-dash broken lines immediately adjacent the solid line showing of the icon define the boundary of the claimed design and form no part thereof.
All of the evenly spaced broken lines illustrate a display screen or portion thereof, and form no part of the claimed design.