I believe it is to take over the Skymark's 380 that had already been built, which is just 2 planes. However, it is a possibility that NH may just trade in the 2 380 with Boeing in exchange for more 788/789 or even 777X (Boeing can also act as a plane leasing company, like SQ in the past had traded in their 343 in exchange for 77W)
If you are talking about NH is going to buy more Airbus models, NH already has an order for A320NEO.