A combination of the noun nug (a nugget of marijuana;high quality bud) and the participle tron (let us get tronned intoxicated on marijuana) resulting in a word that can function with respect to all meanings given.
Someone who is addicted to obtaining money and building wealth. A money addict and fanatic. Breadheads often work more than one full-time job, and some even participate in illicit activities to "obtain the bread".