Out of chlorobenzene and p-nitrochlorobenzene, which one is more reactive towards nucleophilic substitution reaction and why?

p-nitrochlorobenzene is more reactive towards nucleophilic substitution reaction as compared to chlorobenzene. In chlorobenzene, the lone pair on Cl is delocalised with electrons of ring. Whereas in p-nitrochlorobenzene, presence of strong EWG i.e. NO₂ further delocalises the negative charge. As we know, more is the delocalisation, more is the resonance and stable will be the intermediate formed and hence more is the rate of reaction.