[3] Nessman received his Bachelor of Arts degree in social welfare from the University of California, Berkeley in 1981 and later two master's degrees: from San Francisco State University (1988, education) and from Saint Mary's College of California (1995, physical education and recreation).
The De La Salle basketball team under Nessman had a 155–40 record, one section and five conference championships, and four appearances in the NorCal tournament, including a runner-up finish in 1993.
[4] In November 2000, the state Commission on Athletics placed Porterville on probation for a season due to improper benefits provided to men's basketball players.
[4] Nessman returned to his alma mater UC Berkeley for the 2004–2005 to be an assistant coach and recruiter for the California Golden Bears men's basketball team.
[8] Nessman's first season was the first time the Spartans signed a player directly from a San Francisco Bay Area high school in 21 years.
[11] In 2008, the NCAA reduced the number of scholarships for San Jose State men's basketball by two, as a result of an unsatisfactory four-year Academic Progress Rate of 886 (the minimum satisfactory APR is 925) that spanned predecessor Phil Johnson's final two seasons (2003–04 and 2004–05) and Nessman's first two seasons.
[12][13] In 2008–09, Nessman led the Spartans of San Jose State University to the most WAC road victories in eight seasons.
[15] In the 2012–13 season, after a 9–6 start, San Jose State finished 9-20 (3–14 WAC) following the suspension of leading scorer James Kinney.
As a result, the NCAA imposed sanctions on the San Jose State men's basketball program in April 2014 for the following season, including a postseason ban and reduced practice time.
Athletic director Gene Bleymaier stated in response to the sanctions: "Last year, we were faced with a situation that needed to be dealt with in a major fashion.
"[23] In Nessman's first year as athletic director, the Justin-Siena varsity football team won the CIF North Coast Section Division 4 championship.