The former executive director of a Maine nonprofit that serves the poor has been sentenced to 2 ½ years in federal prison for stealing $900,000 from the organization. Thomas Nelson was also ordered Tuesday to pay more than $1.3 million in restitution and back taxes. Prosecutors say the 56-year-old Nelson embezzled the money from the Sanford-based York County Community Action Corp., which provides fuel assistance, food and other services to low-income families. Most of the agency’s budget comes from federal grants. He took the money from 2004 until 2010. The Portland Press Herald, reports that the judge called Nelson’s actions “shameful.” His lawyer says he stole the money to feed a gambling addiction. Nelson apologized in court. He pleaded guilty last year to conspiracy, embezzlement and tax evasion.