Three meets into her high-school career, Nora Pizzella has established herself as a force in the Sac-Joaquin Section. Pizzella, a freshman at Nevada Union, finished second in the large-school varsity girls race Saturday at the Nevada Union Invitational. The finish was the best of her young career. “I’m excited,” Pizzella said after the race. “It took lots of training.” In addition to regular practices at the high school, Pizzella and the rest of the Miners cross country team took to the hills at Mammoth Mountain in early August for high-elevation training. “It helped a ton,” Pizzella said of the offseason …