This is Northern Ireland, which is part of the UK.
If the IRA are “nationalist” in any fashion, then they’re national socialists.
“PIIGS” is a pejorative coined by the EU to cover their own guilt (they are a social market economy, remember); and it’s also part of the very Alinskyite nature of the EU itself.
The IRA are commies, and mostly atheists. Nothing “Catholic”about them (Just like the current Pope)