Cika wannan jumla: A 1983, Nzau shi ne ɗan Kenya na farko da ya ci nasara a tseren marathon na duniya lokacin da ya lashe tseren Marathon na Chicago na 1983. Bayan shekara guda, Nzau ya gama na 7 a cikin duka.
Marathon na maza a wasannin Olympics na 1984. Baya ga tseren marathon, Nzau ya gama na 14 daga cikin 16 da suka gama tseren mita 10,000 na maza a wannan gasar. A cikin 1990, Nzau ya lashe Marathon na Belgrade na farko.