The rapid growth of digital assets has transformed the global financial landscape, creating new opportunities for investment, innovation, and financial inclusion while presenting significant challenges for tax administration. In Nigeria, recent tax reforms have brought cryptocurrencies, tokens, and other virtual assets within the scope of the Capital Gains Tax (CGT) regime, marking a major shift in the country's approach to taxing the digital economy. This paper examines the concept of digital assets, the legal framework governing their taxation under Nigeria's Capital Gains Tax regime, and the administrative and enforcement challenges associated with their implementation. Adopting a doctrinal and analytical approach, the study reviews relevant statutes, policy documents, and recent scholarly literature on digital asset taxation. The findings reveal that although the inclusion of digital assets as chargeable assets enhances tax equity, broadens the tax base, and aligns Nigeria with emerging international best practices, effective implementation remains constrained by regulatory inconsistencies, transaction anonymity, valuation volatility, jurisdictional complexities, limited reporting mechanisms, and inadequate technical capacity among tax authorities. The study concludes that successful taxation of digital assets requires continuous regulatory refinement, improved inter-agency coordination, enhanced digital forensic capabilities, taxpayer education, and greater international cooperation in information sharing. It recommends the development of comprehensive implementation guidelines, strengthened compliance and reporting frameworks, investment in digital tax administration technologies, and balanced policies that promote innovation while safeguarding government revenue. These measures will improve tax compliance, enhance investor confidence, and support sustainable revenue generation in Nigeria's expanding digital economy.