I claim the ornamental design for a display screen or portion thereof with graphical user interface, as shown and described.
FIG. 1 depicts a front view of a first embodiment of a display screen or portion thereof with graphical user interface, showing my new design; and,
FIG. 2 depicts a second embodiment thereof.
The outermost broken lines in each figure illustrate a display screen or portion thereof of the graphical user interface. The remaining broken lines, including all text and numerals shown, illustrate portions of the graphical user interface. None of the broken lines form part of the claimed design.