Increased Cost of Compliance Modernization Act of 2023 This bill increases insurance coverage available to structures in high-risk flood areas under the National Flood Insurance Program (NFIP), commonly known as Increased Cost of Compliance (ICC) coverage. ICC coverage applies to costs related to flood mitigation requirements for repairs to, or the rebuilding of, flood-damaged structures with existing NFIP coverage. Currently, ICC coverage is capped at $30,000. The bill increases this amount to $50,000, or 20% of the maximum amount of flood insurance coverage, with additional coverage available of up to $100,000, or 40% of the maximum amount of coverage. The bill removes the cap on ICC premiums and requires the premium amount to be calculated pursuant to other NFIP rates. Additionally, ICC coverage does not count towards the cap on overall NFIP coverage. Finally, ICC policyholders are allowed to assign the rights or benefits of this coverage to a governmental agency to satisfy certain cost-sharing requirements applicable to mitigation assistance programs.