This routing using to be an amazing deal using United miles, I know it's gone up in price but I think it's still relatively good. Could transfer Chase points to United.

Jetstar also flies that route nonstop and is often pretty cheap. If you have a Chase Sapphire Reserve card, which would let you redeem points at 1.5 cents each against a retail airfare, that could also be a good option.

(Neither of those are very Amex-centric options, but there you go.)