Is It Right ?

the way you phrased the question sounds like you've already formed an opinion.

If the wife isnt Nigerian, is she expected to act like one?

if na oyibo, for example, how should she greet the father in law?

This is how wahala dey start oh.

if its a Naija lady born and raised abroad, then its unfortunate she married a traditional guy who wont understand her or make any allowance for the fact that she's different. Most times all people do is rain abuses on such people for not knowing their culture.

If its a Naija lady from a different culture than the husband, then maybe find a way to tell her that's not how its done in your place. Though why someone who easily takes offence at these cultural issues would marry a woman who doesnt share his mentality, is beyond me.  

If the guy is the kind of person who carries his extended family on his head and considers them more important than his wife and kids, then marrying outside his village is bound to be a disaster.

Am not saying the wife shouldnt respect the in laws, but its not everything that needs to become a major issue. Especially if the wife isnt intentionally trying to be rude but just doing things and showing respect the way she knows how.

na so so wahala everyday. Different kinds of trouble. Naija wife no dey get rest.