Preserving Charitable Incentives Act This bill increases the cap for corporate charitable tax deductions from 25% to 100% of a corporation's taxable income for taxable years beginning in 2020 and 2021. This increase encourages corporate donors (e.g., restaurants and retailers) to donate excess inventory rather than destroying it. The bill allows a carryover of excess inventory into the succeeding taxable year. The bill also directs the Department of the Treasury to revise regulations with respect to the treatment of inventory as costs of goods sold for purposes of the charitable tax deduction.