Mancini was livid with the match officials in the wake of his side's 4-3 victory over the Canaries claiming that home defender Sebastian Bassong should have also got his matching orders as it was his original tackle on the French playmaker that sparked the controversy.
Referee Mike Jones instead opted to give Bassong a yellow card for the offence after consulting with his assistant who had a closer view of the incident which took place on the far touchline.
Nasri by contrast will now serve a three-match ban for alleged headbutt on the Norwich man, which includes a trip to his old club Arsenal on January unless January 13, although the Italian is keen for the club to appeal against the suspension.
Mancini said: "Both players came forward with their heads, so if you are going to send off one, then you have to send off both, not only Samir.
"Samir said he touched his head, okay, but the other player has done the same.
"The linesman has a big responsibility also, because it was not a good decision, it is incredible.
"You want to send off both players? Then, okay, the referee was there, he saw everything. The linesman was behind [the players], he could not see. We will appeal, sure.
"I am disappointed with Samir, and he will pay his fine, but the decision was not correct.
"It was not a red card. It was not a red card."
The City boss is already facing an Football Association probe following his Boxing Day comments after the Sunderland game that referee Kevin Friend had 'ate too much for Christmas.'
He added: "There are two rules for different teams, and I hate this in football and cannot accept this.
"In life, there is only one rule for everyone. This season, I have seen things which are not good."