The Hammers captain, who was branded "irresponsible" when sent off against Fulham, has now scored four goals in his last two matches to pull his side clear of the drop zone
Allardyce slammed Nolan as "irresponsible" after his captain picked up his second red card in just under a month his side's 2-1 defeat at Fulham on New Year's Day.
However, the 31-year-old has returned from suspension in fine form, netting both goals in last week's 2-0 victory at home to Swansea City, before repeating the trick at Villa Park.
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And Allardyce has paid tribute to the former Newcastle United man for the manner in which he has responded following his second dismissal of the season.
"He knew he let himself down, and the [other] players and the club," he said. "He'd been pretty down.
"But he's come back with a new vigour and something to prove, to show his meaning to the team as a captain and a player.
"He's trying to put right what he did wrong with those two silly sending-offs. I think he's doing that.
"Four goals in the last two games. Two goals today showing that he doesn't need to have an Andy Carroll to score goals."
Nolan was substituted on 67 minutes against Villa, but Allardyce revealed his withdrawal was merely a precaution.
"He had a slight tightening of the groin, so he gave us a shout," he added.
"We have a game coming up on Tuesday [at home to Norwich City] and it's very important that he's fit for that, so we didn't take any chances."