No, it could not... Ο καφές=coffee is masculine so that would be "Ο καφές σοκολάτα"
Would that denote chocolate-flavored coffee? And coffee-flavored chocolate would be... what?
By mistake I translated it as the brown coffee. Honestly I don't see reason the greeks wouldn't use both "foods" for the name of the color...
Well, there is the colour σοκολατί, which we mainly use to describe tanned skin or hair dye.
I quite like chocolate bars that have bits of dark roasted coffee beans in them.
That would be ο καφέ καφές, or ο σοκολατί καφές rather than σοκολατής καφές as user I.Schmidt1 wrote, if it's chocolaty brown. :)
To be fair, no one ever says ο καφέ καφές, there is hardly any point to it and it sounds weird!