[mcguire]

The problem is that there exist first-hand and second-hand (i.e. MAGIC intercepts) primary sources for decisions from both sides in the summer of 1945 (https://nsarchive2.gwu.edu/NSAEBB/NSAEBB162/) and they don't really support the theory. (It's possible you could find some reasoning to support the "impress the Soviets" part, but to make that the primary motive would be to ignore the majority.)

Also, keep in mind that Halsey had a bit of a problem with Nimitz and much of the Navy, particularly over the matter of two typhoons and Leyte Gulf, so he may not be entirely unbiased.