This is a reference to the character MC Gusto (played by Chris Rock) from the rap mockumentary CB4. MC Gusto fronts a rap trio with strong similarities to NWA; they have a hit with “Straight Outta Locash.” But unlike (some members of) NWA, CB4 aren’t street at all — MC Gusto’s real name is Albert, and he comes from the LA suburbs. Instead, the thug life he brags about on his records is more or less stolen from the life of a real thug, a local crime kingpin named Gusto who is sent to prison and believes he was set up by Albert.
Here Nas is suggesting that his enemies (likely Biggie; see above) are fake gangsters like MC Locash, spinning invented or stolen tales of street life. Ironically, these same charges would be leveled against Nas by Jay-Z.
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