Paying a Fair Share Act of 2023 This bill requires an individual taxpayer whose adjusted gross income exceeds $1 million (high-income taxpayer) to pay a minimum tax rate of 30% of the excess of the taxpayer's adjusted gross income over the taxpayer's modified charitable contribution deduction for the taxable year (tentative fair share tax). The amount of the tax is the excess (if any) of the tentative fair share tax over the excess of (1) the sum of the taxpayer's regular tax liability, the alternative minimum tax (AMT) amount, and the payroll tax for the taxable year; over (2) certain tax credits. The bill provides for a phase-in of such tax and requires an inflation adjustment to the $1 million income threshold for taxable years beginning after 2023. The bill also expresses the sense of the Senate that Congress should enact tax reform that repeals unfair and unnecessary tax loopholes and expenditures, simplifies the tax system, and makes sure that the wealthiest taxpayers pay a fair share of taxes.