I did a few searches with various terms and couldn't find anything specifically on this.
Suppose several small butterflies ( unforeseen breakthroughs in their work) gives the Manhattan Project greater success, and we have Fat Man and Little Boy in August 1944 ( rather than OTL's Aug 45).
Would it have been used on Germany?
If so, where?
What's the possibility that Japanese observers (perhaps escorted by the Swedish embassy?) would have been allowed to see the devastation and report back to Hirohito in an effort to get the Japanese to give up without nukes having to be used on them?
What are the long term affects on the Cold War, or perhaps does the sight of two flattened European cities make the USSR a bit more conciliatory, fearing the " blood-mad Americans"?