The Serbian moved to Schalke in January 2015 having fallen out of favour under the Chilean, bringing an end a two-and-a-half-year stay in the Premier League
Nastasic was signed from Fiorentina by Roberto Mancini in 2012 and became a first-team regular under the Italian.
However, following the Italian’s sacking, the centre-back made just 13 Premier League appearances with new boss Pellegrini in charge as City reclaimed the title.
Nastasic did not feature at all for City before making the move to Schalke in January during the 2014-15 season.
“City always have a good team with 25 top players, but the coach is only able to let 11 of them play,” he told Goal. “That’s not easy.
“In my first year, I played a lot of games. In the first half of my second season, it was also good. Then I got injured and missed over three months. Then I returned and didn’t play anymore.
“I spoke to Manuel Pellegrini, we’ve talked two or three times. He said he’d give me a chance, but I didn’t feel so. It was a hard time.
“Six months before I came to Schalke, I didn’t play a single game for City. I only played for the national team. I am happier to be here now.”
Nastasic made the move away from City to Germany, but believes the Premier League will be a more attractive prospect to players than ever before following the new television rights deal.
“Every club in the Premier League has an unbelievable amount of money,” he said. “Now they signed a new TV deal. They have totally different possibilities and almost every player can be paid.
“They just ask: ‘How much?’ and then they pay the money.”
Nastasic was signed at Schalke by Roberto Di Matteo but does not fear for his future after the former Chelsea boss was replaced by Andre Breitenreiter.
“It was a pleasure to play under Di Matteo,” he said. “That he left, isn’t a problem. It’s football’s business that coaches change.
“A new coach with new ideas can also be an advantage for the players. Especially because Andre Breitenreiter is good new coach.”
He added: “Andre is a great person. I can see the enthusiasm in his eyes and also feel it, when he speaks to us. He is passionate and likes to communicate, that’s important for me and the team.
“I like his style. Together we can archieve a lot.”