CHATTANOOGA, Tenn. - Nate Piasecki (58 kg/127.75 pounds) and Justin Millard (85 kg/187 pounds) repeated as champions in the FILA Greco-Roman Junior National Championships today at Camp Jordan Arena.    The tournament is normally the qualifying tournament for the United States FILA Junior World Teams. The FILA Junior World Championships are not being contested this year. However, the champions and selected additional placewinners qualify for a reduced rate to compete in Tour de Monde trips later in the year.    Piasecki, who moved up from the 119-pound weight class a year ago, faced another returning champion, Daryl Spackman, in the semifinals of the 119-pound weight class, winning by a 11-0 technical fall. In the finals, Piasecki needed less then a period to defeat Efren Ceballos of Bakersfield, Calif. by a 10-0 technical fall. Spackman, who won the 110-pound title last year, finished third.    Millard also was unscored upon in winning three matches en route to his second 187-pound title, pinning Ryan Ard of the Bulldog Wrestling Club in 26 seconds, winning a 14-0 technical fall over Peter Kuisle of Fairmont, Minn. in the semifinals, and blanking Drew Hageman of Lauderdale, Minn. 6-0 for the title. Millard opened the scoring with a gut wrench 45 seconds into the match and added two more takedowns on bodylocks for a 4-0 halftime lead.    The two wrestlers' performances highlighted a strong run by the eight-man contingent representing the United States Olympic Educational Center (USOEC), based in Marquette, Mich. The USOEC claimed four champions overall, with Joe Espinoza (119) and R.C. Johnson (213.75) also winning titles, and nearly claimed the team title by scoring 45 points. Espinoza won a wild 8-6 match against two-time Wisconsin state champion Luke Smith of Chippewa Falls, breaking a 3-3 tie with a five-point throw early in the second period and holding on for the victory. A two-point gut wrench midway through the first period scored all the points Johnson would need in a 2-1 overtime victory over Eli Ross of the Minnesota Storm.    But Matt Nagel claimed the 152-pound title in the tournament's final match, allowing the Storm to edge past the USOEC to claim the team title with 46 points. After opening with an 11-3 victory over Kevin Lozano of the USOEC, Nagel claimed victories of 13-0 over Grant Ryder of Corvallis, Ore. In the quarterfinals, a fall at 1:01 over John Cox of Grand Haven, Mich. in the semifinals, and a first-period 10-0 technical fall over Bobby Fisher of the USOEC in the title match. Nagel was voted the tournament's Outstanding Wrestler. Californian Marco Lara, the third-place finisher at 138.75, won the tournament's Most Falls Award with three pins in a combined 11 minutes, 6 seconds.    Ben Kjar (110) of Bountiful, Utah, a four-time state champion, was the only high school wrestler to win a FILA Junior Greco-Roman title this year. Kjar scored an 11-0 technical fall over Ohio state champion Mike Compton of Willard in the only match contested in the weight class.    Other champions were Mike Simpson (138.75) of Anaheim, Calif., Darin Harris (167.25) of West Valley City, Utah, and Joe Hennis (264) of Mims, Fla. Simpson and Harris were unscored upon in winning their titles, while Hennis scored a 6-2 victory over Tim Taylor of the U.S. Marine Corps to win his title.    The freestyle competition, featuring men's FILA Junior and women's FILA Cadet and FILA Junior divisions, begins Saturday at 10 a.m. EDT.