Opry Mills has filed suit in Chancery Court of Davidson County today against its insurance company for not paying $150 million in flood insurance, which could delay repairs at the shopping center indefinitely, company officials said today. Its insurers have agreed to pay only $50 million, which is all but depleted from repair work done since the early May floods, said Gregg Goodman, president of The Mills, a Simon Company. Simon Property Group participates in a joint ownership of Opry Mills and is a 50 percent owner.