Nasim started his career as a lecturer in
Govt. College, Multan and then
Government College, Lahore. In 1962 he got a scholarship and went to
Glasgow,
Scotland. In 1966 he got PhD in Biochemical Genetics from
University of Edinburgh. From 1966 to 1973 he was a research officer in
Atomic Energy of Canada Ltd. From 1973 to 1989, he was senior research officer in
National Research Council of Canada. During this period he passed a sabbatical year (1978–79) at
Max Planck Institute,
Tübingen,
Germany, and the Biology Department of
Stanford University. From 1983 to 1989, he taught as adjunct professor in Department of Microbiology and Immunology,
University of Ottawa and from 1984 to 1989 as adjunct professor in Department of Biology
Carleton University, Ottawa. From 1989 to 1993, he worked as principal scientist and head, Molecular Genetics Group, Biology and Medical Research Department,
King Faisal Specialist Hospital and Research Centre,
Riyadh,
Saudi Arabia. From 1994 to 1996, he was executive secretary in Pakistan Academy of Sciences, Islamabad. In August 1996 he was appointed as adviser science,
COMSTECH, Islamabad. ==International involvements==