SECTION 1      Notwithstanding any general or special law, rule or regulation to the contrary, the state retirement board shall credit Nathan R. Mackinnon of Westford, a member of the retirement system, with creditable service for the service he rendered at the Nevada System of Higher Education for the period of July 12, 2017 to April 30, 2021, inclusive, for the purpose of determining his superannuation retirement allowance under chapter 32 of the General Laws. Eligibility for this creditable service shall be conditioned upon payment by Nathan R. Mackinnon to the state employees' retirement system of an amount equal to the amount that would have been deducted under said chapter 32 if he had received regular compensation during the applicable period at the annual rate of regular compensation that he was receiving immediately before this period, together with regular interest on that amount. Such repayment shall be made in one lump sum or in installments, as the state retirement board shall prescribe.