Context. Giant (> 100 kpc) nebulae associated with active galaxies provide rich information about the circumgalactic medium around galaxies, its link with the interstellar medium of the hosts, and the mechanisms involved in their evolution. Aims. We have studied the giant nebula associated with the Teacup (z = 0.085) quasar based on VLT MUSE integral field spectroscopy to investigate whether the well-known giant (∼10 kpc) active galactic nucleus (AGN) -induced outflow has an impact on the distribution of heavy elements in and outside the host galaxy. Methods. We have mapped the oxygen and nitrogen gas relative abundances (O/H and N/O) in two spatial dimensions across the giant nebula and within the galaxy by means of comparing emission line ratios with photoionisation model predictions. Results. The widely studied AGN-driven outflow responsible for the ∼10 kpc ionised bubble is enhancing the gas metal abundance up to ∼10 kpc from the AGN. O/H is solar or slightly higher at the edges of the bubble, in comparison with the subsolar abundances across the rest of the nebula median (O/H ∼0.63 (O/H)⊙). Conclusions. AGN feedback can produce metal enrichment at large extranuclear distances in galaxies (≥10 kpc).