Northern Ireland is part of the United Kingdom (UK). The requirements for working as a nurse or midwife in the UK and EEA (European Economic Area) are different for those who trained outside the UK and EEA.
If you are want to work as a nurse or midwife anywhere within the UK you must gain registration with the Nursing and Midwifery Council (NMC).
Details of the application process can be found on the NMC’s website at https://www.nmc.org.uk/registration/joining-the-register/