Hypothetically: your precision-guided munitions killing only family members of only military officers who haven't yet surrendered to you would be a stronger offense. Your enemy's anti-aircraft guns firing only at their own aircraft, and their tanks driving under your control to destroy their munitions depots, the crews helplessly imprisoned within. Your enemy's civilian populace becoming convinced that their own leadership is crucifying babies and mass-murdering anyone who speaks their language, your soldiers treat civilians well, and their family members are urging them to surrender to you.

Compared to those things, the power of nukes is trivial; all they can do is destroy. You can't surrender to a nuke, and the point of warfare is to convince the enemy to submit, not to damage the ecosystem. Damaging the ecosystem is just a side effect, so it's the wrong way to measure the strength of offensive resources.