An offhand, uncalculated remark from a hysterical woman?
I don't know that much about Nancy Pelosi, but I have had the impression of a savvy politician who thinks about what she says. She holds a position of influence in the House, and I generally think it's a mistake to dismiss statements by such people. (It doesn't mean we have to take those statements at face value, of course.)
China has aided Iran's nuclear program for a long time.
It is dual use.
They also ship chemicals to Iran and other ME nations used for chemical warfare.