Green’s Dictionary of Slang

1. a hat.

1859		Hotten Dict. of Modern Sl. etc.
1864, 1867, 1870		Hotten Sl. Dict.
1883		N. Devon Jrnl 8 Feb. 7/2: [from The Echo] Come, cows and kisses, put the battle of the Nile on your Barnet Fair, and a rogue and villain in your sky-rocket.
1895		Mirror of Life 27 July 14/2: And, oh, it was a sight to see / His Battle of the Nile.

2. in ext. use of sense 1, the head, the mind; also note have a tile loose under tile n.

1915

Sporting Times 3 July 1/3: By unkind treatment [he] drove her off her ‘battle of the Nile’ to a madhouse.