I claim, the ornamental design for a display screen or portion thereof with graphical user interface, as shown and described.
FIG. 1 is a front view of a display screen or portion thereof with graphical user interface, showing my new design; and,
FIG. 2 is a front view of a display screen or portion thereof with graphical user interface, showing an alternative embodiment of my new design.
In the drawings, the broken lines depict environmental subject matter only and form no part of the claimed design. The dot-dash broken lines define boundaries of the claimed design and form no part thereof.