How can I create Chinese webcomics?
What do you mean by "not support Chinese"? You can't input Chinese characters into the generator, or Chinese characters become gibberish, or something else? I tried the website you mentioned, but it requires Flash, so I can't try myself.

Anyway, I typed "webcomics generator" in Google and found a lot of promising results. For instance, https://www.makebeliefscomix.com/Comix/ seems like a really good one. Easy to use, and supports Chinese. Here is a comic I made in one minute. Have fun!