The two tags seem definitely redundant.
taiwan, 53 questions, tag excerpt: "Questions related to the varieties of Chinese spoken in Taiwan."
taiwanese, 10 questions, tag excerpt: "Taiwanese is the people who live in Taiwan, and is also their language. Taiwanese use traditional Chinese to write and record."
Currently there's a little inconsistency in how tags relating to regional varieties are handled. For one, [cantonese] on one hand is the name of the language, but [hong-kong] is the name of the place. The tag [hong-kong] does include some questions loosely related to regional variants of cantonese, but of mandarin as well. Though it makes sense to keep it as is, so that it can be used for questions not strictly related to language.
So I considered that:
- Taiwanese might be confused for the native Formosan language, which should be off-topic
- questions about specific on-topic varieties of Chinese spoken in Taiwan have already their own tag (Hakka and Hokkien).
- like [hong-kong] the tag is used for questions that are loosely related to the language (e.g. culture, local habits, etc.)
I propose to synonymize [taiwanese] in favor of [taiwan]. (Likely requires mod action)