Embodiments of a method for controllably reducing of the flow area of a turbine nozzle component are provided, as are embodiments of turbine nozzle components having reduced flow areas. In one embodiment, the method includes the steps of obtaining a turbine nozzle component having a plurality of turbine nozzle flow paths therethrough, positioning braze preforms in the plurality of turbine nozzle flow paths and against a surface of the turbine nozzle component, and bonding the braze preforms to the turbine nozzle component to achieve a controlled reduction in the flow area of the turbine nozzle flow paths.