The graphic basically puts them in their places. On the right we have Act, National, and NZ First. Act is reasonably far right, National is centre right, and NZ First is populist bullshit make big promises and never have to follow through. NZ First has worked with the left in the past but ultimately their everything-ist views are more right than anything.

Greens are solid left, Labour is centre left, Māori party are specific to a group of people but typically are quite left (but have had a coalition with the right in a different time and place, almost 20 years back).

Opportunity are new kids on the block. They have never been in parliament before, and have shot from 2% to 8% in polls in a short amount of time (actual results are 5.8% at the moment, 5% is required to enter parliament most of the time). Opportunity are explicitly centralist, it's their platform. They campaigned on "stop reversing everything the last government did, let's find some policies both sides can agree on". Their actual policies range hugely, and they have used things like a broad land tax and a UBI to get their name in the media.

I think the most likely outcome (as of now, with 90% of the votes counter) is that the current coalition (National, Act, NZ First) retain power, but if the remainder get over half then Opportunity will likely go with the side that gives them the best deal.