Nobody Have ou Has?

Nobody goes with "has".

Nobody (ninguém) e somebody (alguém) empregam-se com verbo na terceira pessoa do singular. Logo, has.

Gostaria de saber como fica a Tag Question com "nobody" na frase abaixo:

Nobody has complained about our services, hasn't he?
Ou
Nobody has complained about our services, haven't they?

If the subject is nobody, somebody, everybody, no one, someone or everyone, we use “they” in the tag question.

If the main verb in the sentence is have (not an auxiliary verb), it is more common to use do in the tag question.

But:
Nobody has complained about our services, do they? (Amer. English)
Nobody has complained about our services, have they? (Brit. English)

Notice that "nobody has" is regarded as a negative statement of sorts, hence the "have they"?

PP, parece-me que, hoje em dia, os americanos usam 'right', 'okay' etc no lugar da 'tag question'. Os ingleses ainda continuam usando a 'tag question' apropriada.

Thanks for your insight, Marcio. Perhaps it´s a matter of usage this days, I mean, in academical usage (say, at schools) they use the former (or at least they teach it as a subject).
Then as a matter of practical usage, they use "right/okay" an so on...
By the way, we learn and get immersed in the American English, we get so into this brand of English that when we have to communicate with a Brit (cough! Cough!), it may give us the creeps!

Just kidding a little bit, but many say that the British English is harder, less slangy or colloquial. And sometimes more grammatical (meaning their "play with with words" if any, is more sophisticated).