Look at the New Zealand batting lineup. They have explosive batsmen such as Tim Seifert, Rachin Ravindra and Daryl Mitchell. Given this, and given the current state of Zimbabwe bowling, I would say that even a target of 180 is not going to be enough. The only quality bowler in Zimbabwe squad is Blessing Muzarabani. And in recent times, his form has deteriorated considerably. And there are not too many other players there to support him. Given all this, I would expect the Kiwis to win in less than 12 overs.
New Zealand chased down the target of 120 runs in just 13 overs and secured a big win by 8 wickets, losing their two wickets. All the players in the New Zealand squad, especially the batsmen, are T20-style players, so a target of 120 runs is a very easy score for them. Although they lost one wicket for five runs in the beginning, they were able to put pressure on the New Zealand batsmen later, which allowed New Zealand to complete their target of 120 runs in 13.5 overs.