Hi,
There is a GetPlayerController node already for you that you can access from any blueprint! Right click anywhere in your blueprint and search for Get Player Controller. You should see the node and other similar nodes appearing 
However, you might still need to cast it to your own custom controller. You can do this for every one of those Tick Event! just cast once for Event Begin Play and save it into a variable. Alternatively, if you’re sure that your cast will never fail, then right click on the cast node and select “convert to pure cast” and you will no longer need an execution node for it.
Hope this helps