"It was released only in Brazil by local Sega distributor Tec Toy in 1998"
Pretty sure this site carries NTSC ROMs, with some NTSC-J (Japanese) ROMs available too.
"NintenDON'T sue me please haha"
Will there be a ROM available for the Genesis version of Duke Nukem 3D? The only reason I can think of as to why it's not available is because Duke Nukem 3D is still sold on storefronts like Steam.