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.
To give a good competitive match against New Zealand, the target must be big. But Zimbabwe could not do that. New Zealand won by using only 2 wickets against 120. No one in the team could make a big score. The only opening batsman Madhevere got off to a good start but the other batsmen could not do the same. Madhevere managed to score 36 runs although his strike rate was very low at 112. New Zealand managed to chase the target in just 14 overs. Although Tim Seifert could not get off to a good start, Devon Conway did his job very well. Zimbabwe must be confident when playing against big teams, otherwise their performance may deteriorate.