In 1975-1978, Nguyen was a postgraduate student of Karazin University and after graduation successfully defended his PhD thesis “Controllability of Dynamical Systems with Restrictions on Control”. Nguyen is a full professor, the Vice-President of the Vietnam Academy of Science and Technology. In 1979-1983, Nguyen was the Head of the Department of Differentiated and Dynamical Systems of Kharkiv Institute of Mathematics, in 1983-1986 — the Deputy Director of the Center for Applied Systems Analysis at the Institute of Management (Kharkiv), since 1986 — a senior researcher, later — the Deputy Director of Hanoi Institute of Mathematics. In 1997-1992, Nguyen was the Director of the Department of Planning and Financing, and since 2001 — the Deputy Director, and since 2003 — the Director General of the National Center for Natural Sciences and Technology of Vietnam. He was an active organizer of the joint project of the National Academy of Sciences of Ukraine and the National Center for Cutting-Edge Ukrainian Technologies Transfer into the Economy of Vietnam and other countries of Southeastern Asia.

In Vietnam, Nguyen continued studying the mathematical theory of control. He is the author of more than 50 scientific works on the topic in the leading mathematical journals.

In 1990, the Academic Board of the Institute of Mathematics of the Academy of Sciences of Poland awarded him the degree of Doctor of Mathematics.