Nas didn't do the mafioso shyt because of anybody. It was a general trend at the time on the East Coast that was popularized by Kool G Rap and Mobstyle.
He is a Kool G Rap stan, has songs on Illmatic talking about "lamp like Capone", "Uptown was Alpo heard he was kingpin", and "I'm like Scarface sniffing cocaine" has a whole song called The World Is Yours. He was featured on AZ, Kool G Rap, and Raekwon's albums all mafioso albums in '95 and going by Esco on The Infamous.
Nas catching shyt for doing R&B/rap collabs with Jodeci, Lauryn Hill, and R. Kelly but nobody say nothing when Wu-Tang working with SWV and Method Man putting out songs with Mary J. Blige.
Man, foh.
This post summed it all up!!!!