Prior to the signing into law of the Petroleum Industry Act (PIA) 2021, the tax regime of companies engaged in petroleum operations in Nigeria was primarily regulated by the Petroleum Profit Tax Act (PPTA). The subsequent enactment of the PIA 2021 has adjusted and introduced major fiscal clauses in relation to the Nigerian petroleum industry, particularly in the upstream petroleum sector. The main objective of this article was therefore, to conduct an overview of the administration and enforcement of the fiscal governance under the extant petroleum industry regulatory legal framework in the light of some novel clauses introduced therein. The article adopted a library-based doctrinal research methodology by relying on both primary and secondary sources of information. The various sources of information were evaluated and inferences drawn there from. Findings of the article revealed inter alia, that the PIA has incorporated a number of fiscal innovations, including but not limited to a dual profit tax regime for upstream petroleum operating companies, namely the hydrocarbon tax (HT) and companies income tax (CIT) in lieu of the petroleum profit tax (PPT) under the PPTA. The authors therefore, recommended that if the Nigerian government will succeed in creating a dynamic fiscal framework that promotes investments in the Nigerian oil and gas industry, balancing the profits with attendant risk and attracting revenues to the government, compliance with the clauses of the statute becomes imperative both by the government and the relevant stakeholders in the sector.