When a taxpayer has unused losses from multiple nol years, reduce taxable income in chronological order for the nol tax years, beginning with the:?

I believe it would be earliest allowable tax year.

According to current regulation, we are allowed to Carryback NOLs to prior years to claim a refund for 20 years or less.

If for example that the allowable tax year only 2, the amount that should be used is the earliest of the 2 years.