Green’s Dictionary of Slang

nobbler n.3

also nobler
[fig. use of nobble v.2 (1); it ‘gets hold of you’]

[mid-19C–1950s] (Aus.) a small measure of spirits; thus the drink itself.

In derivatives

nobblerize (v.)

[mid-19C–1950s] (Aus.) to drink spirits, usu. as part of a group.