Dr. Nabeel was appointed to the Department of Animal Production in the College of Agriculture and Forestry / University of Mosul in 1974 as a teaching assistant for veterinary medicine, and as a veterinarian responsible for health supervision of sheep and cattle fields in the college.
In 1977, he started his master study at the College of Veterinary Medicine / University of Baghdad to obtain a master's degree in Animal Physiology to contribute after returning to the College of Agriculture as an Assistant Lecturer for teaching Physiology and Reproductive Physiology.
His services were transferred to the College of Veterinary Medicine / University of Mosul in 1980 to participate in the practical lessons of pharmacology. After obtaining a PhD in Biochemistry from the University of Aston / Birmingham / United Kingdom, and after returning to Iraq, he worked as a lecturer and Assistant Professor at the College of Veterinary Medicine at University of Mosul, during which he contributed to teaching Biochemistry and Clinical Chemistry at the College of Veterinary Medicine and the College of Science at University of Mosul. As well as in the College of Veterinary Medicine and College of Education of the University of Duhok.
In 2005, he held the position of Dean Assistant for Scientific Affairs and Postgraduate Studies at the College of Veterinary Medicine / University of Mosul. His contributions include chairing postgraduate committees, guiding students, quality programs, as well as participating in scientific and preparatory committees for many conferences and seminars.
He was assigned the position of Director of Scientific Affairs and Cultural Relations at the University of Mosul from 2012 to 2015, during which he contributed to activating the activity of cultural relations, delegations and twinning between the University of Mosul and Arab and foreign universities.
During his working period, he contributed to many scientific activities, including publishing many scientific researches, supervising postgraduate students (Master’s and Ph.D. students at the University of Mosul and University of Dohuk), many postgraduate students exams, participating in scientific conferences in Iraq, Arab and foreign countries, in addition to his role As a member of the Chemical and Biological Handling Control Committee at the University of Mosul, Head of the Chemical Import Unit at the University of Mosul and Secretary of the Editorial Board of the Iraqi Journal of Veterinary Sciences (Scopus).
His career service at the College of Veterinary Medicine / University of Fallujah was extended in 2015, during which he was assigned the position of Head of the Physiology, Pharmaceutical and Chemistry Department and a member of the Advisory Board for the Presidency of the University of Fallujah, in addition to teaching Biochemistry and Clinical Chemistry.
After his retirement in 2018, he joined Al-Noor University College to teach General Chemistry, Biochemistry and Advanced Clinical Chemistry to students in the departments of medical Laboratory Techniques, Dentistry and Pharmacy, in addition to holding the position of Dean Assistant for Administrative and Financial Affairs.