No Lenin, no NEP...Know Lenin, know NEP
I would argue that there wouldn't be a NEP without Lenin, assuming the Bols held on. If they did, then Trotsky would almost certainly be calling the shots, as the head of the presumably victorious Red Army...his vision for postwar Russia was a harsh militarization of life, including "labor armies" and "labor fronts"...He would have imposed a harsh barracks socialism on Soviet-ruled areas...which would have produced probably even stronger reactions from disaffected peasants and minorities (see the Antonov rebellion in Tambov, for example). My guess is, a Trotsky-ruled militarized USSR was not viable for several reasons, economic, political, and social...However, who would have replaced him? Trotsky would have purged Stalin most likely, as well as Zinoviev and Kamenev, his opponents IOTL; Sverdlov was dead from Spanish flu; perhaps Bukharin? My guess is, a wholesale collapse of the young Soviet system and something else taking shape altogether...Much work needs to be done here.