Not really tbh. I just think South Africans are cool and that they have badass accents and that’s just what comes to mind when I think of a rugged, gritty mercenary :p Also I think I’d been watching Neill Blomkamp films over and over at the time I thought up that headcanon and just thought “yo what if Kruger from Elysium was female” and then somewhere out of that, my version of Nadine was born. Except, you know, she’s not working for the oppressors but is a ruthless sonofabitch because she’s all about revenge against the Bad Guys.
Also I felt that her being South African would kind of fit in to the Peace Walker timeline and the general narrative. I haven’t expounded on this in any of my fics yet, but a little spoiler for her backstory is that she joined MSF after quitting SAP, which she’d joined in 1972 when they hired their first female officers. She really didn’t like the orders coming down from the upper brass or having to enforce apartheid bullshit, so the moment she caught wind of MSF, she got the hell out of dodge and went to mercenary work. I also figured it’d be a fitting ~bonding moment~ for her and Kaz later on because there wasn’t a lot of advancement opportunities for women in the police force back then, and Kaz would be able to empathize because of his similar experiences with JSDF.