There are some districts in the US that hold training for their substitute teachers and then issue them with these substitute teacher certification documents. I've heard from more than one expat in Taiwan that the Taiwanese government will accept this as a teaching license and qualify one to teach in public schools.
I am an actual licensed teacher and for each public school teaching job I've had or applied for in Taiwan, I've been asked to walk a school rep or employee through the process of looking up the record and current status of my license online. I can't see that a substitute license would work in this case. But you are free to try it and see how it works out. Please do report back on how it goes for you.