that is the same for kids with nationality with or without household registration. The CSL program is for taiwanese kids who returned to taiwan within 1 year from non-chinese speaking country staying there for more than 2 years, and foreigner kids who came to taiwan within 2 years. The process is the same for both kids.
If you or your parents read Chinese, here is the link to the introduction of the program at Xinsheng.
http://www.snes.tp.edu.tw/index.php?op=download&file_id=19605
You will find some other documents here.
導覽>> * 首頁
>> * 檔案中心
>> * 辦法規章
>> * 輔導室
>> * 語文教育班
http://www.snes.tp.edu.tw/index.php?op=showgallery&file_category_id=164
士東國小 in tienmu may also have a CSL program.
臺北市士林區士東國民小學語言教學教育班實施計畫
http://163.21.216.2/語教班/index.htm
I noticed that those documents say foreign parents of kids should be on work ARC, and taiwanese parents should work or study in Taiwan. An employment certificate is listed as a required document for application. I’m not sure whether this is an optional,and if it is mandatory, how strictly the rule is applied.
One more note is in Taiwan nationality and citizenship are separated.