I think it's impossible to say. It would be undialectical to say "he would've made the same decisions as Stalin" as so much of what Stalin did was in the context of the civil war within the party that happened in response to Lenin's death.

I think if the contradictions within the revolution and party came to a head during his lifetime and Zinoviev, Kamenev, Trotsky, Bukharin, etc tried to seize control, Lenin dealing with them would make the "Great Purge" in our timeline look like a fucking tea party.