Notwithstanding any reference in this chapter to Chapter 19 of this title, any taxpayer not subject to taxation under Chapter 19 of this title may claim the credits allowable under § 2011, § 2021, § 2040 or § 2070 of this title against the tax imposed by Chapter 11 of this title; provided, however, that the amount of credit claimed by an individual under Chapter 11 of this title shall not exceed 50% of the amount of tax imposed upon such individual by Chapter 11 of this title for such taxable year.