keep one's nose clean(I went back to my desk and sat down and spent a little time wondering why a fairly important local racketeer like Menendez would think it worth his time to come in person to my office and warn me to keep my nose clean, just minutes after I had received a similar though differently expressed warning from Sewell Endicott. (Raymond Chandler)ART Vancouver)
poke one's nose(into something, etc.: As agile as a cat, he is continually on the lookout for something, poking his nose everywhere, wanting to know the why and the wherefore of everything)
stick one's nose(во что-либо – into something: I never liked the way my neighbours stuck their noses into each other's business. – ...суют (свой) нос в чужие делаART Vancouver)