User blog comment:South Kaioshin Daniel/Strawhat Pirates nationalitys/@comment-3181121-20110405201440

This was answered in an SBS:

Nami - Swedish

Luffy - Brazilian

Zoro - Japanese

Usopp - African

Chopper - Canadian

Franky - American

Brook - Austrian

Sanji - French

Robin - Russian

You got most of them right :-)