Nomonhan was in '39, and by that point neither party wanted war. The Soviets wanted to focus on Europe, occupying their Molotov-Ribbentrop conquests and preparing a defence against the Germans (if they were as naive as sometimes thought, why were the vast majority of their troops in the west in the first place?). Japan had no desire to get a major land power into its was in China, least of all the one's who could invade Manchuria. It was to the benefit of neither side to escalate things. We need a clearer PoD.