Why does this sentence 「授業中は、おしゃべりしないの」use しない instead of するな


So I got this sentence

> 授業中は、おしゃべりしないの

from this [article](https://www.tofugu.com/japanese-grammar/particle-no-
nominalizer/) in Tofugu.com.

It's supposed to translate to "Don't chat during class!".

Why does it use しない instead of するな? I thought to say "don't" as a command
you're supposed to use するな?

