Athletic director Gene Bleymaier announced the move on Wednesday, a day after San Jose State's season ended with a 67-49 loss to UTSA in the WAC tournament in Las Vegas.
The Spartans went 9-20 this season, their second straight campaign with only nine wins. Nessman had an 86-161 record in his tenure and led the team to the College Basketball Invitational in 2011.
San Jose State is looking to upgrade the program before its move to the more strenuous Mountain West Conference next season.
