A/Prof Nga obtained Histopathology Fellowships from both the Royal College of Pathologists of Australasia and the United Kingdom. Her area of subspecialty interest is Cytopathology. She is also a Fellow of the International Academy of Cytology, and completed her Cytology Fellowship at QEII Hospital in Western Australia, under the generous mentorship of Drs Felicity Frost and Gregory Sterrett.

A/Prof Nga is a council member of the Singapore Society of Cytology, and editor of their biannual newsletter, CytoPage. She is also a frequent speaker in local and international pathology conferences, and has been an invited keynote speaker conferences in Australia and India. Her particular areas of interest are in thyroid, salivary gland and pancreatic cytology. She has also authored a cytopathology book entitled Practical Diagnostic Approaches In Non-Gynaecologic Cytology, which is published by Springer (2022). A/Prof Nga also co-authored a chapter in the WHO Classification of Tumours: Paediatric Tumours (Papillary thyroid carcinoma). In 2024, A/Prof Nga delivered  a Short Course in the USCAP Annual Scientific Meeting in Baltimore, on the topic of lymph node cytology.

A/Prof Nga is a keen driver of innovation in education. She has created several online teaching resources including Pathweb, a comprehensive online learning  resource with several thousand registrants from over 130 countries. She is also the creator of the Pathweb Teacher YouTube channel which has more than 20000 subscribers. In addition, her Cytopathology website, Cytoweb, is featured in the International Academy of Cytology website as an educational resource.  In 2019, she was the recipient of the National University of Singapore Outstanding Educator Award. A/Prof Nga has also been featured in the 2023 Power List of The Pathologist, an online magazine documenting news in all aspects of pathology.

Outside the clinical realm, A/Prof Nga has also been an elected fellow of the NUS Teaching Academy, in which she has helmed the Teachers Who Inspire team, producing videos of inspiring teachers from various faculties. Since 2023, she has also been a member of the University Teaching Excellence Committee (UTEC), which determines the recipients of the highest teaching honours in NUS.

In addition to her work in undergraduate teaching, A/Prof Nga is also keenly interested in the mentoring and training pathology residents. She has served as Core Faculty in the NUHS Pathology Residency programme since its inception.