The emergence of COVID-19 has produced unprecedented change in daily life activities leading to major impacts on psychological wellbeing and sleep among individuals worldwide. The study aimed to assess levels of fear, stress, anxiety, depression, and insomnia among undergraduate nursing students in four countries two years after the start of the pandemic. An international, multi-centre cross-sectional electronic survey was conducted between December 2021 and April 2022. An on-line questionnaire was distributed via Qualtrics® and JISC® software. Instruments included the Fear of COVID-19 Scale, the Perceived Stress Scale, the Hospital Anxiety and Depression Scale and the Insomnia Severity Index, and a demographics and academic background questionnaire. The independent variables included demographic and academic backgrounds, while fear level, stress, anxiety, depression, and insomnia were the dependent variables. A total of 918 undergraduate nursing students from KSA, Oman, UK, and UAE were participants in the study. Students presented with stress (91.6%), anxiety (69.1%), depression (59.8%), and insomnia (73.2%). The participants’ mean Fear of COVID-19 Scale score was 12.97 (SD = 6.14). There were significant positive relationships between fear of COVID-19, stress, anxiety, depression, and insomnia. Undergraduate nursing students experienced moderate to severe levels of Fear of COVID-19, stress, anxiety, depression, and insomnia two years after the onset of the COVID-19 pandemic. Psychological intervention and peer support are needed to reduce the long-term adverse outcomes of mental health problems and insomnia. It is important to introduce education about crisis management of infectious disease during pandemics into the nursing curriculum to increase student knowledge and improve their preparedness for such emergencies.