Well, he's able to create hearts holding every aspect of every heart. Even though he didn't create the hearts for any of the worlds he is capable of making hearts of that collosal size. The reason some many people bend to his will is because they have heart made by him. Even over a nobody he still has the power bend their will. This is where Lein differs from the bunch.
For now, Lein cannot defeat Chance, even if he can stand up to him. Chance is currently immortal, however even so he has seals on his power, true they keep him alive, but at the cost of freedom to use certain powers. BtW what are your over-all thoughts on him (Chance)?