National Oceans and Coastal Security Improvements Act of 2019 This bill revises the National Ocean and Coastal Security Fund. (The fund supports programs and activities to protect, conserve, and restore ocean and coastal resources and coastal infrastructure.) Specifically, the bill revises the maximum amounts that may be used to provide grants from the fund; details new eligible uses for the fund's grant program, including for restoration, protection, or maintenance of living ocean, coastal, and Great Lakes resources and their habitats; requires the National Oceanic and Atmospheric Administration and the National Fish and Wildlife Foundation to award grants from the fund to eligible coastal states based on a specified formula; and specifies additional requirements for coastal states to be eligible to receive funding from the fund.