Assuming my chain is showing that it's worn and getting close to needing replacement due to chain 'stretch'. I know you can flip single speed chainrings to extend their life when they become worn. Can I flip the chain around to extend it's useful life? I doubt it would double it due to some overlap in wear on rollers, but possibly extend it a bit by putting load on the opposite side of the pins.
I would say that this won't have any effect.
Flipping the chainring on a single speed makes sense as you use the other side of the teeth on the chainring which have not been used before. But with the chain it's a different story: The stretch is independent of directions so reversing its direction won't change anything. Also on the small "rolls" in the chain links on which the chain lies on the chainring I wouldn't expect any effect as they aren't fixed in the links but can rotate and therefore should wear out equally all around their circumference.