We propose and experimentally realize subwavelength light localization based on the optical nonlinearity of a single nonlinear element in nanoplasmonics-a split hole resonator (SHR). The SHR is composed of two basic elements of nanoplasmonics, a nanohole, and a nanorod. A peak field intensity occurs at the single spot of the SHR nanostructure. We demonstrate the use of the SHR as a highly efficient nonlinear optical element for (i) the construction of a polarization-ultrasensitive nanoelement and, as a practical application, (ii) the building up of an all-optical display.