He has repeatedly rejected the charges, saying he is being politically persecuted by Ma Ying-jeou, the current president, for his anti-China views.
He was indicted in November and is standing trial on charges of embezzling $3.15m from a special presidential fund while in power, receiving bribes worth at least $9m and laundering some of those funds.
On Wednesday, he was indicted on further charges. Prosecutors accused him of taking the equivalent of $8.8m in bribes between 2002 and 2005 from a local banker.
They allege that the money was camouflaged as either political donations or funds to promote Taiwanese interests overseas.
Chen faces life in prison if convicted.