Magnetically confined plasmas, such as those produced in the tokamak JET, contain measurable amounts of impurity ions produced during Plasma-Wall Interactions (PWIs). The impurities including high- and mid-Z elements need to be controlled within tolerable limits, to ensure they do not significantly affect the performance of the plasma. This contribution focuses on documenting the nickel (Ni) behavior in the plasma during Ion Cyclotron Resonance Heating (ICRH) and comparing the Ni levels during operation with the ITER-Like Wall (ILW) that consists of a tungsten (W) divertor and a beryllium (Be) main wall, with levels during operation with the previous Carbon (C) wall. Ni release during ICRH is presented as a function of the applied power level, relative phasing of the antenna straps, plasma-strap distance, different plasma configuration and compared with release during Neutral Beam Injection (NBI).