Maynard, who has been eased back into action recently with substitute appearances, opened the scoring in the 3-1 win.
Marvin Elliott restored City's lead midway through the second period before substitute Brett Pitman applied gloss to the scoreline in injury time. But it was the man Pitman replaced with 15 minutes remaining who drew special praise from Millen after his side moved seven points clear of the npower Championship relegation zone.
"You can see the contribution Nicky has made to the team," said Millen. "He's quick, he's strong and he can finish.
"I wanted to start him and for him to last 75 minutes is a great effort. I certainly thought he had 45 minutes in him but he didn't look rusty.
"He scored his goal and showed his quality and his movement on a difficult pitch. Hopefully he's okay for Saturday."
Source: PA
Source: PA