THE RED GAMBIT SERIES

I am in June 1946, about a couple months after the Japan nukes, and wondering why we are not using them against the Reds.

I know there is at least one more (which was intended for Japan) and according to Our World in Data, the US had 9 nukes in 1946 in reality.

Are we sparing them because they are human and the Nips weren't?

Contains spoiler - Nope. In reality, the pressure from the Allied nations notto use the bombs on Germany would have been immense... plus there was actually no need. In RG, I allowed for the Germans/Poles/Czechs etc to feel slightly miffed at the possibilities of atomics being used on their soil. Once the Red Army's logistics collapsed and the retreat started, I mainly figured there was no need until it was a matter of retaliation.