Knight, who was second in the Washington state 3A cross country championships last month, ran 19:32 to finish behind Sarah Baxter of California (19:17) and Mary Cain of New York (19:21).
Finishing right behind Knight was sophomore Alexa Efraimson of Camas, the Washington state 4A champ, who ran 19:34.
Amy-Eloise Neale, the 3-time Washington 3A harrier champ from Glacier Peak HS in Snohomish, finished eighth in 19:45.
Neale recently declared that she would join Knight as an incoming freshman at the University of Washington next fall.
The Nike Cross Nationals features many of the country's top high school runners and teams in what amounts to the closest thing to a true national championship meet.