At the Nile, the objective was to remove the French fleet from the war. Destroying or trapping it would cut the associated army off from movement and resupply, leaving its fate to later British political and military choices. That strategic purpose explains Nelson's readiness to attack as soon as the fleet was found. A fleet battle could therefore decide the freedom of action of an army far inland.
Chapter · 5:40-7:07
The Nile as a fleet-destruction mission
At the Nile, Nelson's operational aim was to eliminate the French fleet and isolate the army it supported.