JAKARTA, June 29 (Reuters) - Nissan Motor Co plans to double the capacity of its car manufacturing plant in Indonesia, said the chief executive of Indomobil , an agent for Nissan car sales in the country. Indomobil's president director Gunadi Sindhuwinata was speaking to Reuters on Tuesday ahead of a planned press conference in Jakarta by Nissan's CEO Carlos Ghosn on Nissan's plans for the Indonesia market, which is expected to see record car sales this year. (Reporting by Janeman Latul;