If your EOI is selected, so you get to put in an ITA, then everything about your qualifications, experience, health and character checks out when the CO investigates...
...and at that point, you don't have a job offer from NZ...
...then, as the last stage of the assessment process, you will be interviewed by your CO, for him/her to check your employability. (Someone with a job offer doesn't normally get interviewed, because obviously, an NZ employer already has decided they are employable.)
There are lots of old threads talking about the Immigration Interviews, and what questions can be asked. Broadly, the CO has to check whether the applicant knows about the NZ way of life and systems, and how their career works within that, to check that, if admitted, this person will be likely to cope, and to make a good impression so as to be able to land a skilled job and make a contribution to the country. There are three possible outcomes. If all looks good - Residence. If the CO finds some knowledge but ignorance of some matters - a Job Search Visa (deferred Residence), which is a visa for nine months, to land a skilled job (and Residence), or leave. If the interview shows up a serious lack of knowledge and preparedness - the visa will be refused.
To sum up, the final decision rests on how you show up at interview. You can prepare for the interview by researching old threads on here, also by finding out everything you can about NZ, and the employers you might work for and how to contact them, and also by making a recce trip. If you do a trip having made previous contacts, of course you might get a job offer and not need to be interviewed at all.