You haven't picked any nodes so it will always go to the one node, usually the one with lowest UID or that was created first. To pick a random one in this case it would be something like Movement = 1 - Pick random instance of WalkNode - Find path to WalkNode.X, WalkNode.Y.
Also I don't know what you want exactly in your game but based on that logic your Sprite is going to be getting told to path to new nodes on the way to other nodes. You might want to try using On Arrived with your logic if you want them to move to a node first before finding a new one.