The USSR already had a record of extensive cooperation with the Nationalists earlier on, Stalin only started backing Mao much later on. This question depends on circumstances like how long the civil war lasts and the extent of Soviet support for the communists.
Mao was too independent to bet set up by Stalin as a government in exile or something. Various European communists who spent WW2 in Moscow became the core of Warsaw Pact governments later on, but the Great Purges affected these emigres as well. The only survivors were sycophantic Stalinists, its hard to see Mao falling into line like Walter Ulbricht or Wanda Wasilewska.