Depends. Does the German-Soviet military cooperation proceed as IOTL with German personnel training in the USSR? If so, wouldn't it make more sense to aim to restore 1914 borders in Poland in order to maintain their shared alignment against the Versailles world order, as was seriously considered in the first Polish-Soviet War? At any rate I'm still skeptical that he would not realize that it's a bad idea unless there's a serious distraction like Hitler or Germany to divide the world's attention. I guess you could see him wanting to have Germany and the USSR going at Poland together, to dilute the connotation of Red expansionism with an admixture of German revanchism to draw the lion's share of the world's ire.Ah, how bout this for a compromise:
Trotsky advocates the Soviet Union to take Poland and the Baltics as buffer space against the West. Or to take the Baltics in a preparatory move for an invasion of Poland. Stating that the Red Army is strong enough (on paper) to take these areas and this will put Germany; France, Britain and USA on the back foot.
How does this sound?
If there's no German-Soviet cooperation at all, I don't think Trotsky would be willing to risk diving headlong into Poland alone and getting dogpiled by France, Germany, and Britain.
This is of course just my opinion. It's your choice at the end of the day. This is your TL, not mine.