It's no surprise that, in English slang, to "nick" something (as in Slapnicker) is to steal.
Fraud
The illicit senses of 'nick' start in the later 16th century in reference to what was later 'chiseling': cheating or defrauding debtors and the poor for one's own benefit (sense III.15.a).
"How doth he nick the debter now by hault exacting wayes."
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