In the case of Wales - it is a country and a nation, but not a sovereign state. The Parliament of UK is still the supreme government. It can change the status of Wales anytime. Thus, it cannot be admitted into the UN. As a country it can have its own sporting teams in the FIFA World Cup and other international leagues. read more
State, nation, and country can all be used to indicate a “country” like in the article and the US states do act very similarly in their relationship to the US government as Scotland, Wales, and NI do within the UK. read more