Three, not two.
No. Ireland and Norway are two separate countries.
Norway and Sweden (And Denmark).
Norway and Sweden are two separate, sovereign countries that happen to be neighbors in the region known as Scandinavia.
Luxembourg has borders with Belgium, France and Germany.
Norway and Sweden.
Norway and Sweden
Scotland and Norway
Norway and Iceland.
Norway and the UK
Norway and Denmark.
Norway and Sweden
Two: Norway and Iceland.