U.S. government won't fight Nacchio sentence ruling

* Appeals court found trial judge miscalculated sentence

* Prosecutors will not appeal circuit court ruling

LOS ANGELES, Aug 17 (Reuters) - U.S. prosecutors said they will not appeal a ruling likely to result in a reduced prison term for former Qwest Communications International Inc (Q.N) Chief Executive Joseph Nacchio, who was convicted in 2007 of insider trading.

The 10th U.S. Circuit Court of Appeals last month concluded that Nacchio's six-year sentence and $52 million penalty was improper because the trial court incorrectly calculated the illegal gains from his 2001 stock market trades.

It did not specify a shorter sentence, but ordered the trial court to reconsider the punishment.

Justice Department spokeswoman Laura Sweeney said on Monday the government decided not to appeal the ruling. She declined to elaborate.

Nacchio was convicted of 19 counts of insider trading, after prosecutors accused him of selling his Qwest stock when he learned that Qwest could not meet its financial targets.

His lawyers argued for a prison sentence of 41 months to 51 months, as recommended under federal sentencing guidelines, based on insider trading profits of $1.8 million. Prosecutors argued for a sentence of 70 months to 87 months.

Nacchio's conviction was hailed as a victory over greedy corporate chieftains.

Others convicted of financial crimes in recent years include Tyco International Ltd's (TYC.N) Dennis Kozlowski, WorldCom Inc's Bernard Ebbers and ImClone Systems' Sam Waksal.

Nacchio began serving his sentence at a minimum security prison camp in Pennsylvania in April. He is waiting to hear whether the U.S. Supreme Court will review his conviction. (Reporting by Gina Keating; Editing by Phil Berlowitz)