ChainFinder.Object is the prototype of the class, it’s not supposed to be used. You’re supposed to create an instance of the class that you get back from FObjectFinder.
FYI there’s another option to FObjectFinder – which I used to myself before I learned about this: Change your Chain declaration to TSubclassOf<USkill>. It will show up in the Gameinstance blueprint where you can set it to what you want. Then you can use it in your C++ code.
Just like with FObjectFinder, you still need to create a new object from the class.