Wormholes (Theoretical objects that they are) can I ask how you'd be able to control the gravitational shear force so that the chimney dose not implode? Even if Santa used wormholes, that still dose not account for what people have said and that been his ability to visit all the worlds homes in on evening he still has to obey the law of Quantum Mechanics that states "Two objects Cannot Occupy the Same Space At the Same Time" therefore he can not have the ability to "Dimension Shift" that is to appear to an observer to become multiples of the same object that can merge back into a single whole again and negates the possibility of any sort of time-travel which is allowed under Special Relativity.
Regards to you.
Cyber-Angel