2007 Chrysler Town & Country - Additive for Knocking

My car is knocking 2007 town and country sounds like timing chain. Can I put a thick additive to reduce knocking till I get it fixed

You can do anything you want. I would suggest the knocking is more likely a rod knock than timing chain. Pour in STP or similar but you are driving on random borrowed time. It could fail right after you pour the stuff in or run for 6 months. If either the chain or rod fails you will be replacing the engine.