The ex-Manchester City winger's three-goal haul helped Tim Sherwood's men seal a 5-3 victory over the League Two visitors in their Capital One Cup second-round tie.
Villa were beaten 1-0 by then-League One side Leyton Orient in last season’s second-round tie under former manager Paul Lambert and Sherwood’s men looked in danger of suffering the same fate at times against their fourth-tier opponents.
County opened the scoring after 16 minutes through Genaro Snijders’ 25-yard blast, before home debutant Adama Traore equalised in the 24th-minute with his first goal for the club thanks to a well-worked assist from Jack Grealish.
The visitors were back in front in first-half stoppage-time, however, when Jonathan Stead dispatched a spot-kick after goalkeeper Mark Bunn had brought down Izale McLeod just inside the box.
The home side were level again five minutes after the break, as Grealish set up Sinclair for a simple tap-in after another forceful run, but former Villan Graham Burke came back to haunt his old club six minutes later with an outstanding curling shot to give the Magpies the lead for a third time.
A Sinclair penalty 12 minutes from time took the game to extra-time, though, before the 26-year-old winger completed his hat-trick in the 99th-minute and substitute Joe Bennett rounded off the scoring soon after to set up a third-round clash against arch-rivals Birmingham City.
Here are some of the images from the high-scoring affair at Villa Park.