。
I'm totally hands-off on this matter.
Literal
I this matter [regarding-に関して] no-touch [reason-なんで].
ノータッチ ('no-touch') is wasei-eigo — combining English 'no' and 'touch' to mean 'uninvolved, hands-off.' なんで is the casual contraction of なので ('because'). The particle omission (俺 without は/が) and abbreviated reasoning (なんで with no conclusion) are characteristic of blunt casual male speech.