Abstract: The present invention relates to a replaceable nozzle insert adapted to be removably received and secured within the atomization port of a spray nozzle. The spray nozzle is then, in turn, used to atomize a two fluid mixture, typically slurry and gas. The nozzle insert is configured to provide for the use of highly abrasion-resistant materials in the construction of the insert, thereby significantly increasing the average life of the nozzle insert. The improved features of the nozzle insert include a two-piece design having an insert sleeve and an insert retaining cap. The insert sleeve portion of the nozzle insert has an interior fluid-conveying and gas flow passages therein and can be received into the atomization and inner body ports of the spray nozzle. The insert retaining cap cooperates with both the insert sleeve and the spray nozzle to secure the insert sleeve in place in the spray nozzle.