That's what we're afraid of. Not saying that they wouldn't deserve it, but there's this little thing called "escalation". China doesn't like India. India nukes Pakistan, China could see that as a possible threat to themselves, and it could be "goodbye New Delhi, Mumbai, Hyderabad, etc.".
After that, who knows? Punishment there should be, but NOT the Big Boom.
China doesn’t like India. India nukes Pakistan, China could see that as a possible threat to themselves,
Or China could see it as the end of a problem that could get worse.