China has maintained a nuclear “no first use” policy—i.e., a policy “not to be the first to use nuclear weapons at any time and under any circumstances” and “not to threaten to use nuclear weapons against non-nuclear-weapon states”—since its first nuclear test detonation in 1964 (see, e.g., Wikipedia).

It appears that China has only made one nuclear threat in its history, around two decades ago: “In 2005, Chinese major general Zhu Chenghu said that China might retaliate with nuclear weapons if the United States attacked Chinese forces in a conflict over Taiwan” (Wikipedia).

Related questions:

• Will the U.S. make an official statement before 2030 threatening nuclear use in the defense of Taiwan?
• Will China launch a full-scale invasion of Taiwan by the following years?
• If China invades Taiwan before 2035, will the US respond with military force?
• If China launches an invasion of Taiwan before 2035, and the US intervenes, will China attack the United States?