[2][3] In the 1976 Wisconsin Class A Basketball Tournament, Nimphius led South Milwaukee to three victories and the state championship to complete a 25–0 season.

Nimphius scored 30 points with 11 rebounds in the 45–43 Finals victory over Coach Dick Bennett's Eau Claire Memorial team.

He led the team in scoring and rebounding, playing alongside Byron Scott, Sam Williams, Alton Lister and Fat Lever.

Nimphius began the 1980–1981 season playing in Europe for Rodrigo Chieti of the Italian Professional League, averaging 18.7 points and 10.5 rebounds in ten games.

[12][13][14] On September 2, 1981, Nimphius was waived by the Denver Nuggets and immediately signed as a free agent by the Dallas Mavericks the same day.

[15] As an NBA rookie in 1981–1982, under coach Dick Motta in Dallas, Nimphius played in 63 games with 27 starts, as the Mavericks finished 28–54.

Mark Aguirre, the number one overall pick in the 1981 NBA draft, Jay Vincent and Rolando Blackman were fellow rookies.

Nimphius split time with Cummings and averaged 7.9 points, 6.3 rebounds, 2.1 assists and 1.8 blocks in 27 minutes per game.

Dallas made the playoffs, where they defeated the Seattle SuperSonics 3 games to 2, before losing to the Los Angeles Lakers 4–1.

[24] In 1986–1987 Nimphius played 38 games for the Clippers, averaging 7.8 points and 3.5 rebounds before he was traded to Detroit for two high draft picks.

The Pistons, with Isiah Thomas, John Salley, Bill Laimbeer, Adrian Dantley, Joe Dumars, Dennis Rodman, Rick Mahorn and Vinnie Johnson advanced to the Eastern Conference Finals.

The Pistons were defeated 4 games to 3 in the Eastern Conference Finals by the Boston Celtics with Larry Bird, Kevin McHale, Robert Parish and Dennis Johnson.