News of the letter and subsequent state investigation broke just weeks before the 2006 election. Sanchez won by 24 percent.
Nguyen told investigators he had nothing to do with the letter, and that he only saw an English version of it before it was printed. He said it was the work of a young campaign staffer, whom he fired. But another former campaign worker testified that he was directly involved, even laughing when a staffer told Nguyen he couldn't officially know about the letter.
"It is a verdict from the community," Nguyen told the AP. "I accept it, and there's nothing I can do about it."
The jury was hung on another charge, which alleged that Nguyen had a young staffer take the blame for the letter.
His sentencing is in February. He faces up to 20 years in prison.
Sanchez took some heat herself this year when she said, "The Vietnamese and the Republicans are [trying] -- with an intensity -- to take this seat, this seat with which we've done so much for our community."