The France striker has been linked with United as he battles to force his way into Chelsea's starting XI.
Former United scout Mick Brown told Football Insider: “From what I hear, Man United are certainly interested.
"I’m told he’s on their list of targets and one they could look to snap up either in January or the summer.
“He’s one of these modern-day players where he’s not really a striker, not really a midfielder, and not really a winger. He’s sort of a combination of all three. So when you look at Amorim’s Sporting team, the forwards are all quick and they play off the back of defenders and put them under pressure.
“Nkunku strikes me as the sort of player who would fit into that perfectly. He’s also more than good enough to play every week at this level."
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