It is not yet clear whether Sapient will hire a like-for-like replacement for Nurko.
Before Nurko joined Nitro in 2006 he was UK managing director and global head of innovation at FutureBrand.
In his new role Nurko will be based in London and report to Patrick Smith president and COO of FutureBrand Worldwide.
Smith said: "Chris is passionate about innovation and the commercial success of ideas. A consummate brand strategy expert, he will fit perfectly back into the Futurebrand fold."
In March this year FutureBrand restructured its UK management, which resulted in the departure of managing director Jasmine Montgomery.
FutureBrand has offices in 16 countries including New York, Rome and Paris. Clients include Procter & Gamble, Microsoft, Nestle and Nokia.