Monsignor Charles J Brown is an unusual appointment in that he does not come from the Vatican's diplomatic corps.
Instead, he has worked at the Holy See's Congregation for the Doctrine of the Faith (CDF).
This means he will be deeply familiar with the Catholic Church's response to child sexual abuse which was central to the CDF's work.
The decision to make him papal nuncio is being viewed as an indication of the thought that Rome has invested in the appointment.
In November, the Irish government decided to close its embassy to the Vatican in what was described as a cost-cutting measure.
The decision was greeted with dismay by Cardinal Sean Brady, Ireland's most senior Catholic cleric.
He said he was "profoundly disappointed" by it.
Damning report
Earlier this year, the Vatican recalled its special envoy in Ireland after a damning report on the Irish Catholic Church's handling of child abuse by priests.
Papal Nuncio Giuseppe Leanza was called back to Rome to discuss the impact of the Cloyne Report which showed how allegations of sex abuse by priests in Cork had been covered up.
The report led to angry condemnation of the Vatican by Prime Minister Enda Kenny in the Irish Parliament.
In a blistering attack, Mr Kenny accused the Church of putting its reputation ahead of child rape victims.
Monsignor Brown's nomination has been approved by the Irish government. However, it is standard practice for the Vatican not to confirm or deny the nomination until it is officially published by the government.