I claim the ornamental design for a display screen or portion thereof with graphical user interface, as shown and described.
The sole FIGURE is a front view of a display screen or portion thereof with graphical user interface showing my new design.
The outer perimeter broken lines in the drawings represent a display screen or portion thereof and form no part of the claimed design. The dot-dash broken lines define a boundary of the claimed design and form no part thereof.
The grayscale tones shown in the drawings represent a contrast of appearance.