In the case of both countries there is no official (de jure) capital, but there is a de facto one. This is described in the relevant Capital infos in English, German, Spanish and French, since the information is mentioned in the relevant Wikipedia articles in the given languages. In the case of Norwegian the situation is trickier, since there are three listed sources. The question therefore is whether to include an NB Capital info, and if so, what.
For Nauru, the Country names, capitals and national holidays brochure lists Yaren as the capital without any qualifiers (for comparison, for the Netherlands and Tanzania, it does mention their special situations, so it's not the case that being a brochure it's excessively brief).
The SNL however does mention that there's no official capital:
Det er ingen offisiell hovedstad, men regjeringen har tilhold i Yaren.
Wikipedia also mentions that Yaren is just the de facto capital.
Again, the brochure does not mention anything special about the capital.
Nor does SNL AFAICT.
Wikipedia does however say that Bern is only the de facto capital.
(See also #334.)
The obvious would be to copy directly from SNL:
Det er ingen offisiell hovedstad, men regjeringen har tilhold i Yaren.
but it's a bit verbose.
Perhaps this?
Nauru har ingen offisiell hovedstad; Yaren er regjeringssete.
("har ingen offisiell hovedstad" has some google results).
(@Vages, if you have time, though obviously this isn't urgent.)
Nauru har ingen offisiell hovedstad; Yaren er regjeringssete.
is a great translation!
As for official sources not mentioning the capital's "de facto"-ness: I don't think I've ever come across a Norwegian tabular representation of country and capitals that acknowledges capital ambiguities (other than the South African tri-capital solution). I don't know why, but the Norwegian foreign ministry does not have an official "a country must have a capital", so you're not treading on any toes. 馃榿
Thanks for the confirmations and for the fast reply! :)
Most helpful comment
is a great translation!