His testimony came as the defense began presenting its case during the fourth week of the $6.7 million fraud trial of Brown. Other defense witnesses Monday testified about the curriculum and educational programs she developed for the schools.
Nunery said his one-man firm was paid $60,000 for its consulting work.
He was named a deputy superintendent under Arlene C. Ackerman in 2010 and became acting superintendent after she departed in 2011. Nunery left the district in August 2012 and has resumed work with PlusUltre.
Brown is charged with defrauding her network of schools and then participating in a scheme with two other former administrators to cover it up.
Nunery said Brown decided to retain him based on his experience leading the charter school division of Edison Schools Inc., where he oversaw 25 schools across the country from 2005 to 2007.
He said his firm worked for Cynwyd in the summer and fall of 2008 to try to improve communications with K12.
"Anything I could do to be helpful to Dr. Brown - that's what she wanted," said Nunery. His consulting work with Cynwyd ended in November 2008.
Under contracts, K12 was entitled to be paid 15 percent of Agora's revenues. Cynwyd's share was 7 percent.
Prosecutors contend that Agora's board never approved the Cynwyd contract and that Brown fabricated the document.
Jurors also heard from Howard Lebofsky, an assistant general counsel with the Philadelphia Gas Works who served on the boards of two of Brown's charter schools.
Lebofsky said he joined the board of Brown's Laboratory Charter School in 2003 through his friendship with Harold Hairston. The former city fire commissioner is Brown's brother and was chairman of the Lab board at that time.
Lebofsky said he was impressed with Brown and the quality of the education at her schools.
He said he agreed to become chairman of Agora's board in the summer of 2008 when Brown called to describe problems the school was facing, including low test scores and operational issues with K12.
Lebofsky said Brown told him K12 was enrolling students before obtaining the educational records needed to place them at the appropriate instructional level. "It was pretty clear from the beginning that there was lack of meaningful communication," Lebofsky said.
He blamed K12, not Cynwyd, for the problems.
"I was perfectly satisfied and felt Cynwyd was absolved of any fault," Lebofsky said. He recalled writing letters to K12 and meeting with K12 officials to try to resolve the issues.
The trial resumes in federal court Tuesday.