You'll need a stronger change to avoid war with the US
The US-Japan war chain of actions was only slightly related to the alliance with Hitler.
The Japanese actions in China and Indochina triggered an US embargo, and Japan really depended on the resources embargoed. After that, Japan had two options: Let their industry and everything asphyxiate, or try to take the US out of the western side of the Pacific.
Oh! And Japan wanted Phillippines, by then a colony of the US. That could be problematic.
Maybe you'd want to substitute Roosevelt with another Chamberlain or a fascist sympathizer.
But the question is about the USSR and peace with the US is an assumption.
Maybe the IJA is actually capable
In 1945, the Imperial Japanese Army stationed in Manchuria was a backwater occupation army, left with half of their theorical numbers and that half being essentially militia, the IJA being the long neglected branch of the armed forces and with a morale that could amount to a crap and half.
Okay, after finishing that paragraph I can not think of any way that the Manchurian army could hold their ground short of making them the focus of the overall strategy (i.e somehow the Siberian expansion axis would have been elected, but that's a total change that nullifies the context of the question).
So we're left with weakening the Soviet army, or preventing the invasion altogether.
Maybe the Nazis could chew what they bit, or at least for longer
By 1943 the Allies (including the USSR) were sure enough of victory against Germany that they planned what the USSR would do against Japan and started planning and allocating resources for the invasion of Manchuria.
Maybe the US is a true hermit and doesn't send materials to the USSR and that ends up hampering their war effort quite a bit. Maybe Moscow falls and the USSR suffers a heavy loss in leadership that prolongs the war some years. Maybe a time traveler convinces Hitler to stop being an idiot and prepare for winter, again prolonging the war.
Anything that makes the fate of the Nazi-Soviet war undecided in '43 and '44 makes any Manchurian plan nonsensical.
Maybe the USSR simply leaves Japan alone
Stalin's focus on gains after the war was in Europe and Japan being honorably neutral was really convenient for the USSR.
The most interested party in the Soviets aiding against Japan was Roosevelt. But here we're assuming the US sits on its butt so there is no push for Stalin to break the neutrality pact any soon.
So maybe you have already made that change, but for different reasons. :P