United won two of their league games last month, with 5-2 victories coming against Fulham and Aston Villa, and Sørensen hit hat-tricks in both matches.
The Magpies also recorded a 2-1 Premier League Cup success over Notts County and a 2-0 Checkatrade Trophy win against the same opponents, with Sørensen on target in both games to take him to eight goals for the month. Overall, he has 12 goals so far this campaign.
The five-man shortlist was decided by the Premier League's Football Development Panel after PL2 managers nominated the best performance by an opposing player in each of their league matches in October.
Also nominated are Joshua Barrett of Reading, Swansea City's Yan Dhanda, Tyreece John-Jules of Arsenal and Lasse Sorensen of Stoke City. The panel will decide the winner, which will be announced later this month.
Sørensen's team-mate Cal Roberts was nominated for September's award, but lost out to Tottenham's Oliver Skipp.