Your text is bound to a function, but the function doesn’t return anything. If you’re using UMG widgets, you don’t need to use a HUD blueprint at all - that’s using pure Slate, the old way to make HUDs. All you have to do is call Create Widget passing in the class of the widget blueprint then call Add To Viewport on the return value of Create Widget from some other blueprint like your PlayerController or something.
Though you still need to put some logic in that Get Text 0 function, like GetPlayerController>Cast>GetScore>IntToText>Return.