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 outermost broken lines in the FIGURE illustrate a display screen or portion thereof and form no part of the claimed design. The remaining broken lines in the FIGURE illustrate portions of the graphical user interface that form no part of the claimed design.