Affordable Care Coverage Expansion and Support for States Act or the ACCESS Act This bill temporarily expands the health insurance premium tax credit. It also establishes a Federal Medicaid Program for states that have not yet expanded Medicaid to certain populations. Currently, in order to qualify for the health insurance premium tax credit, an individual must, among other criteria, have an annual household income of at least 100% and up to 400% of the federal poverty level and not be eligible for minimum essential coverage, such as affordable coverage through an employer. The bill removes the income limitations, and it allows individuals with income of up to 138% of the federal poverty level and who are eligible for employer-provided health insurance or small employer health reimbursement arrangements to qualify for the tax credit. The bill's changes apply for tax years 2024-2026. The bill also establishes and provides funds for a Federal Medicaid Program beginning in 2027 to provide coverage to the Medicaid expansion population in states that have not expanded Medicaid pursuant to the Patient Protection and Affordable Care Act. (The act allows states to extend Medicaid coverage to all adults under the age of 65 with incomes of up to 138% of the federal poverty level.) The program must offer at least the same benchmark coverage as under Medicaid. The Centers for Medicare & Medicaid Services must contract with Medicaid managed care organizations or other third-party plan administrators to administer the program.