Nankel Stuardo Solorzano, 46, of Clifton, Passaic County, faces several federal charges.
Authorities say they seized 40 kilograms of fentanyl, which is equivalent to five million lethal doses.
Large quantities of meth and crack cocaine, as well as multiple weapons, were also seized in the bust.
Prosecutors say Solorzano kept the stockpile of drugs in an apartment complex garage.