The Millers looked to be heading for an eighth home defeat of the season as they trailed to Matty Blair's 63rd-minute opener until Nardiello, 30, popped up with his 15th goal of the season deep into stoppage time to earn an unlikely point.
But the player would not have been on the pitch had he had his own way after asking to come off to protect a niggling groin injury.
The Millers had already made their three substitutions by then, though, so Evans told him to keep going.
"I've got such a belief in Nardiello at the minute. He has been fantastic for two months, he really has," Evans said.
"He was asking to come off because he was feeling his groin and I just told him he had as much chance of coming off as my missus.
"I told him to get in the box when we got forward and he got one chance and put it away."