Sorry to miss your post, I'm not very often here recently.
In my opinion the chain swings like it should. What could mislead you:
You modified anchor position offset, so chain won't swing in YZ plane if this is what you expected.
This chain is connected with ball joints. Due to cummulating numerical errors the chain may go off the plane after some time (however I'm not observing such behavior). To avoid it use hinge joint if your goal is to have bicycle-like chain.
Proportions of the chain in 3D picture will be different (and more natural) than in 2D Graph, because apparently I left non-uniform scales there for x and y axes.
The mesh reference becomes invalid once assigned to the object. Instead you should get the object's drawable reference and use "To More Specific Class" primitive to be able to use SetMeshParams method again (picture attached).
You may use "Find Object" block to find an object by name and then get its Drawable property.