We aren’t provoking @#$%. If anything, China has been the source of any provocation; it’s been openly threatening its neighbors for years.
Taiwan is not recognized as an independent state by China, the UN, or the United States. Taiwan's representatives were expelled from the United Nations fifty-one years ago as being unlawful. The US has adopted the one-China policy. We have no legal right to send a politician in an official government plane to visit anywhere in China without permission from the government of China.
If Nancy were to obtain a visa and take a commercial flight to visit as a tourist, engaging in no official political business, no problem.
The only countries who maintain diplomatic relations with Taiwan are Belize, Eswatini (formerly Swaziland), Haiti, Marshall Islands, Nauru, Palau, Saint Kttts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, and Tuvalu.
https://www.un.org/ga/search/view_doc.asp?symbol=A/RES/2758(XXVI)
United Nations Proclamation 2758
2758 (XXVI). Restoration of the lawful rights of the People’s Republic of China in the United NationsThe General Assembly,
Recalling the principles of the Charter of the United Nations,
Considering that the restoration of the lawful rights of the People’s Republic of China is essential both for the protection of the Charter of the United Nations and for the cause that the United Nations must serve under the Charter,
Recognizing that the representatives of the Government of the People’s Republic of China are the only lawful representatives of China to the United Nations and that the People’s Republic of China is one of the five permanent members of the Security Council,
Decides to restore all its rights to the People’s Republic of China and to recognize the representatives of its Government as the only legitimate representatives of China to the United Nations, and to expel forthwith the representatives of Chiang Kai-shek from the place which they unlawfully occupy at the United Nations and in all the organizations related to it.
1976th plenary meeting, 25 October 1971.
We have trade relations with Taiwan, and agreements to arm it for its own defense. We’ve had that since the early 1950s. Communist China may not like it, but it has accepted it for some 70 years.
You also forget that Taiwan believes that it IS China, and the legitimate government of China; and that the communists are the illegitimate government of China. Remember, the Chinese nationalists never surrendered to the communists in the Chinese Civil War; they are still IN China (though concentrated in a very small area of China).