We 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 our new design; and,
FIG. 2 is an enlarged front view of the graphical user interface, shown separately for completeness of illustration.
The evenly spaced broken lines illustrate a display screen and electronic device as the environment of a display screen or portion thereof with graphical user interface and form no part of the claimed design. The dot dash lines define the boundary of the claimed design and form no part thereof.