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 second embodiment.
The dot-dash lines in the figures illustrate the display screen or portion thereof, and define the boundary of the claimed design. The broken lines form no part thereof.