Green’s Dictionary of Slang

1. a (small) loan, unlikely to be repaid.

1915

Drew & Evans Grifter 85: ‘I am the owner of several fair-sized wads of notes’ [...] ‘You will be able to stand a “nip” then’.

2. one who responds favourably to cadgers, a ‘soft touch’.

1919		N.Z. Truth 21 June 1/7: For a cert he has a nipping roster, / And tots up nips like a bold bill poster.
1937		Bulletin (Sydney) 4 Aug. 21/2: Most ‘bucks’ would be good nips for [...] a handout from their always loaded tucker-boxes.
1947		D. Davin For the Rest of Our Lives 51: We were all pretty plastered and we got the nips on to some more beer.