Spouse of Northern Irish / UK Citizen

[jjpmcat]

Hi All,
My apologies if this question has been asked several times before. Here is my current situation. I am a Northern Irish / UK citizen holding an Irish passport. My husband is from Taiwan. We had been living in the Republic of Ireland for the past year and half, however due to Covid I lost my job. I now have work in Northern Ireland. My husband has a Stamp 4. He has gone back to Taiwan for a couple of months and will return in April. His stamp 4 is up for renewal in April, but I’m thinking of just applying for his settlement visa for the UK now that I’m up here. What I wanted to ask is can he fly into the North on his visa exempt and apply for his permission to reside in the north with me or will he have to apply for a visa before arriving in UK? Thank you in advance for your help.