The official NieR Twitter account recently stated that the game's cumulative sales had exceeded 7.5 million copies worldwide.
You'll be delighted to hear more than 7.5 million copies of NieR:Automata have been sold or shipped to date.
— NieR Series (@NieRGame) April 23, 2023
Thank you for your love and support! pic.twitter.com/4KztzBi8la
Nier: Automata is a 2017 action role-playing game developed by PlatinumGames and published by Square Enix. It is a sequel to Nier, itself a spin-off of and sequel to the Drakengard series.
Source: Twitter