President Augusto Pinochet and Chile's other military chiefs will meet Aug. 30 to choose a presidential candidate, expected to be Pinochet, whose name will be alone on a yes-or-no ballot later this year. A decree published Monday in the government bulletin said Gen. Pinochet, who is army commander, and the heads of the air force and national police last week set the date for their August meeting. Choosing the nominee Aug. 30 indicates the referendum will be in October. Under the 1980 constitution, the vote must occur no less than 30 days and no more than 60 days after the nominee is chosen. Pinochet said in a speech July 7 it would take place in ``no more than 90 days.'' The 72-year-old general has been president since the coup in September 1973 that ousted the late President Salvador Allende, an elected Marxist. Pinochet's fellow commanders are Gen. Fernando Matthei of the air force, Adm. Jose Merino of the navy and Gen. Rodolfo Stange, national police commander. Their decision on a nominee must be unanimous, the constitution says, and if they cannot agree within 48 hours, the nomination will be made by majority decision of an eight-member National Security Council. If a majority of voters ratifies the choice, the candidate chosen will begin an eight-year presidential term in March. If not, an open election will be held in 1990, when congressional elections are planned. Opposition politicians expressed no objections Monday to a vote in October. Ricardo Lagos, a Socialist, told journalists the opposition had expected the referendum to be held Sept. 11, the 15th anniversary of the coup, and a later date provided more time to campaign against it. Lagos is co-leader of a coalition working for rejection of the military candidate. It plans to make its own count of the vote with 20,000 volunteers serving as monitors at polling stations. Patricio Aylwin, president of the Christian Democratic Party, the country's largest, said announcing the nomination date so far in advance ``is good news,'' but he and Luis Maira of the Christian Left Party said the government must take other steps to ensure a fair vote. A specific step they mentioned was lifting the state of emergency that allows the government to limit political activity and press freedom. This will be the first vote for president since Allende won the office in 1970. More than 6 million of the 8 million eligible voters have registered to participate.