Born in Leningrad in 1962, Nesis studied radiochemistry at the prestigious Lensovet Leningrad Institute of Technology. After graduation he worked as master supervisor at the Baltic Shipbuilding Yard (the largest and one of the oldest in Russia, est. 1856), which produced a variety of ships including nuclear icebreakers and submarines. In the early 1990s, Nesis left the shipyard to set out as an Entrepreneur, opting to work for himself rather than for the state.

The ICT ('Investments, Construction, Technologies') Group, founded by Nesis in the early 1990s, is now one of the largest privately owned investment and industrial companies in Russia. It is headquartered in Moscow and has a large office in St. Petersburg. It invests in, develops and manages assets in wide range of industries, including the banking and financial industry, metals and mining, precious metal production, heavy engineering, Logistics, construction and development.

Together with a small group of Business partners, he first concentrated on the production of materials derived from uranium deposits located in the deserts of Uzbekistan. In 1991, the same group of entrepreneurs embarked upon a new venture to invest in the shipbuilding and metals industries. In 1993, their company became known as the ICT Group. In the same year, having made his fortune, Nesis returned to the Baltic Shipbuilding Yards as its controlling shareholder and Head of Board of Directors.

As of March 2012, Forbes put Nesis's personal wealth at approximately $3.1 billion, putting him at No.367 in its list of billionaires and making him No.31 in Russia.