While Murdoch holds and supports the spread of staunchly conservative views, I don't think he wants to go down in the history books as attempting to plunge the US into dictatorship.
It's not about the scenario where Trump actually wins the electoral vote. It's about Biden actually winning the electoral vote, but Fox, Trump, and right wing media sowing enough doubt in half the country that a "coup" is taking place and Biden isn't lawfully President and that their supporters need to support the "legitimate" President by any means necessary.