Nintendo announced their Fiscal Year Ended March 2022 Earnings Release / Financial Results on May 10th, 2022. Pokémon Brilliant Diamond, Pokémon Shining Pearl and Pokémon Legends: Arceus have now sold over 10 million units.

Operating Results and Financial Positions for the Fiscal Year Ended March 31, 2022

Looking at software, among titles released this period, Pokémon Brilliant Diamond and Pokémon Shining Pearl sold a combined 14.65 million units and Pokémon Legends: Arceus sold 12.64 million units, marking sales of more than 10 million units for each.

Looking at software, sales grew beyond 10 million units for Pokémon Brilliant Diamond and Pokémon Shining Pearl, both released in November 2021, and for Pokémon Legends: Arceus, released in January 2022.

Sourcse: https://www.nintendo.co.jp/ir/pdf/2022/220510e.pdf and https://www.nintendo.co.jp/ir/pdf/2022/220510_7e.pdf

Top Selling Title Sales Units - As of December 31, 2021

Pokémon Sword / Pokémon Shield 24.27 million pcs.
Pokémon Brilliant Diamond / Pokémon Shining Pearl 14.65 million pcs.
Pokémon: Let's Go, Pikachu! / Pokémon: Let's Go, Eevee! 14.53 million pcs.
Pokémon Legends: Arceus 12.64 million pcs.

Source: https://www.nintendo.co.jp/ir/en/finance/software/index.html