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; and,
FIG. 2 is another front view thereof, as shown in a display screen environment.
The broken line showing of the display screen in FIG. 2 is for the purpose of illustrating portions of the article and forms no part of the claimed design. The dot-dash broken line in all FIGS. represents the bounds of the claimed design and forms no part thereof.