TOKYO, May 12 (Reuters) - Nissan Motor Co is in advanced talks to take a roughly one-third stake in Mitsubishi Motors Corp with a $1.8 billion investment as Mitsubishi struggles with a scandal over falsifying fuel-economy data, two people familiar with the matter said early on Thursday.

The Nissan and Mitsubishi Motors boards will decide on the roughly 200 billion yen capital and business tie-ups on Thursday, making Nissan Mitsubishi’s biggest shareholder with a stake over 30 percent, said the sources, one from each carmaker.

Press officials for the companies could not immediately be reached for comment.

The news comes just hours after Mitsubishi said it had enough cash to weather the scandal and warned incorrect data may have been used for more of its cars.

Mitsubishi last month admitted to overstating the fuel economy of four of its models - small cars sold in Japan, including two under Nissan’s badge.