You will need an import and export license, which costs NT$10,000 to get including company registration. (Easiest if you can get it in a Chinese partner’s name, I use the one of my missus)
However, if you are thinking of importing a number of special items, such as food, then you need a special license.
Getting stuff into supermarkets is hard and expensive, there’s too much stuff wanting to get in, however if it’s especially appealing, then it might be easier.