I'm pretty sure he mentions it on Hate me Now, Rise & Fall and You Owe Me if you count the "every continent love when I spit it" line.Nas himself doesn’t care. As one of the more consistently selling mainstream rappers of the past 30 years Nas has surprisingly little boasts about his sales. I can name probably only three verses where he brags about his record sales over the course of THIRTY YEARS. and the crazy thing is none of those verses were doing bis peak in the 90’s when he was doing superstar numbers.
I see you your point tho, he's on the more modest side one could say.