Apparently China is building a facility which will churn out new nuclear subs. You can read about it here:
It's one thing to build subs, and another to use them effectively.
But their very presence will pose a threat to US aircraft carriers and SSBNs, so perhaps another giant arms race is now underway.
Are you happy now?
By the way, I never encountered a Chinese sub during my time in the US Navy, but if I had I'm confident we could have defeated it in combat.
Of course, that was over 30 years ago, and things may have changed.