We report the design and first results of a reconfigurable RF-encoding particle (REP) for chipless RFID tag, based on a Nafion conductive-bridging random-access memory cell. The developed tag consists of a modified shorted dipole as REP, equipped with a copper-Nafion-aluminum metal-insulator-metal (MIM) nonvolatile ionic-bridging switch. The MIM switch is similar to an RC parallel network, which tunes the electrical length of the resonator. The chipless tags switch between two different resonant frequencies, in the set and reset states of the switch. An electrical model is also developed for the REP to explain the mechanism of switching. The experimental results are in close agreement with the simulation results using commercial electromagnetic simulators. This letter is a proof of concept of electronically reconfigurable chipless tags based on integrated switches which have the potential to be directly printed along with the tag.