You need to get a refrence to the object, either by “Get All Actors of Class” if the actor is in the world. You can get do a “Get” off the array pin of the “Get All Actors of Class”.
Or you can create an interface or dispatcher on the “BP_Motion_Controller”.
EDIT: Or create a refrence to the hud in the controller and run your logic in the controller. Try not to use bindings in UI elements as they rtun on tick even when you do not require them to be running.
Or you can “Get player controller” and cast that way
All depends on what your controller is for…