The Judge's decision a week ago tossed out an earlier order to freeze 12 billion US dollars in assets belonging to Petroleos de Venezuela S.A., or PDVSA.
Chavez spoke to PDVSA employees in a nationally televised address.
"It's a national celebration, because this is an historic victory. This is a moral, legal, political, economical, technical... a great victory. I'm proud of you."
Exxon Mobil decided to seek international arbitration with PDVSA last year, after Chavez nationalized a heavy oil project in the crude-rich Orinoco River basin.
The company wants at least 5 billion dollars in compensation, but Venezuela insists the assets are worth less than 1 billion.
Exxon Mobil later won court orders in the UK and other countries to freeze PDVSA's international assets to ensure it would be paid for the project and lost future revenue.