nationality/country of origin DS 160 form

Hi my hubby is applying for a Visit Visitor for USA . He holds a British passport but was born elsewhere . The questions on the DS160 are really ambiguous and asking for country of origin/ nationality . I see it as his country of origin is one place , nationality another . He doesn't hold dual nationality . Can anyone help advise / please . Many thanks

In the form there is one section asking for the place (country) of birth and another that asks for the country of origin/nationality, which can be different like in this case.

Regarding the last one, the help section says:

"Enter all nationalities you currently hold and all nationalities you have previously held, regardless of whether you have formally and/or legally relinquished the nationality..."

So he needs to respond accordingly. See pages 7-8 in the official DS-160-Example