On a rain-affected day on the grass courts on the south coast of England, the second seeds took just 43 minutes to rout wild-cards Nicole Melichar of the US and Anna Smith of Britain 6-0, 6-1 in the semi-finals of the Wimbledon warm-up tournament.
The Taiwanese-Swiss duo did not face a single break point and converted five of eight to complete a second victory over Melichar and Smith in a week, after they also defeated the same pairing 6-3, 6-3 in the semi-finals of the Mallorca Open the previous week.
Chan and Hingis were due to face Ashleigh Barty and Casey Dellacqua in the final after press time last night.
The Australian duo ousted third seeds Timea Babos of Hungary and Czech Andrea Hlavackova 6-2, 6-3 in 60 minutes in the earlier semi-final.
The Taiwanese-Swiss duo had a 1-0 career record against the Australians after a victory in the round-of-16 in Miami earlier this year as they looked to add to their titles at Indian Wells, Rome, Madrid and Mallorca.