Can your plugin generate a cuopon

The Woocommerce Reviews add-on does not provide this feature, although, it is a planned feature of the upcoming Review Notifications add-on.

Site Reviews does provide a hook to trigger something after a review is submitted, so you could also use this hook.

With that hook, you could do something like this:

if ($review->isVerified()) {
    // send email with coupon here
}