"I really, really, really didn't think that I would be transferred for €30 million, to think that I would arrive, where people were expecting a lot from me, the fans excited about me and you find yourself in the reserves, play zero, zero, nothing in the Europa League or the league," he told Telefoot.
Mikel Arteta left the 19-year-old out of the Premier League and Europa League squads which meant he could only feature in the reserves and the EFL Cup.
"I was in the squad once in the league cup. It hurt me, it affected me. I don't think I left too early. When you feel ready you have to go. I don't think I left too early. These things happen. I believe in myself," he added.
"For me the best choice, best decision was to join Nice because there is a good project, a good team, a good level of ambition, who like to play in a certain way.
"It feels good to play and to have consistent game time, I am young, I am 19, and it is by playing matches like this that you improve. You see what mistakes you make and you correct them."
Saliba also said he didn't think a year ago that he would be back in Ligue 1 after securing his Arsenal move.
"Honestly, if you told me a year ago, I honestly would not have believed you," he said.
Nice do not have an option to buy Saliba as Arsenal view the 19-year-old as an exciting prospect for the future but Arteta and his coaching staff believe he needs regular game-time elsewhere to toughen him up for Premier League action.