You still mad huh.
Nas was at 15mil sold in 2015 in the US alone. Since then Life Is Good got certified gold, he's released multiple albums and streaming nets him around 100k albums sold a year off Spotify alone. Add in overseas sales and you easily get to what I said: around 20mil.
For overseas sales...
Nas has multiple gold (100k+) albums in the UK: Illmatic, IWW, I Am, Stillmatic, God's Son, and the greatest hits album. He has multiple silver (60k+) albums in the UK: Nastradamus, SD, HHID, and Distant Relatives.
Nas has two plat (100k+) albums in Canada: IWW and I Am. He has multiple gold (50k+) albums in Canada: Illmatic, Nastradamus, Stillmatic, God's Son, SD, and Distant Relatives.
musiccanada.com
Nas has one plat (100k+) album in France: IWW.
You can search the UK certs on BPI. You can search the Canadian certs on Music Canada. Wiki includes most of the certs as well as links to them. Wiki is also missing some sales data (for instance Illmatic being double plat, and IWW being triple plat, in the US).
Nas is one of the most successful US rappers overseas...ever.