If Chinese Communists retreated to Formosa

What if the Nationalists won the Chinese Civil War and the Communists fled to Formosa?

Formosa would likely become a contained but Soviet-supported Pacific base, reversing Taiwan's historical strategic relationship with mainland China.

The Nationalists might initially welcome their rival's retreat from the mainland and keep watch on the island. The United States could initially see the Communists as contained in one place. Regular Soviet fleet visits would change that calculation by making Formosa a Pacific refuge for Soviet naval forces. In this scenario, the island becomes a position that others would seek to bring out of the Soviet orbit. An immediate new war is not expected, but the strategic problem differs from the historical alignment.