Nasri has missed the last four games because of a calf complaint, while defender Mangala has been struggling with a groin injury.
However, the pair are available for this weekend's clash at the Etihad Stadium, leaving Yaya Toure and Wilfried Bony - who will play for Ivory Coast in Sunday's Africa Cup of Nations final with Ghana - as the hosts' only absentees.
"We have no injuries, we have a full squad. Mangala and Nasri are fine and will be in the squad," Pellegrini said.
"Samir Nasri is important for the team but we cannot just think that because he can play we will win."
Both of City's Premier League title wins have been secured on the final day of the season and they will need to fight back in order to claim a third, with Chelsea leading the way by five points.
But Pellegrini believes last weekend's 1-1 draw at Chelsea could be a turning point in his side's campaign.
"Other teams will drop points. The last two times this team has won the title, they’ve come from behind," Pellegrini added.
"It was not a good January but I believe that the game against Chelsea can be the switch for our performances."
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