GO:0035782

The directed movement of a mature natural killer cell guided by a specific chemical concentration gradient. Movement may be towards a higher concentration (positive chemotaxis) or towards a lower concentration (negative chemotaxis). A mature natural killer cell is a natural killer cell that is developmentally mature and expresses a variety of inhibitory and activating receptors that recognize MHC class and other stress related molecules. [CL:0000824, GOC:BHF]