Onyekuru only joined Everton from Eupen last summer for £7m but was immediately loaned out to Anderlecht.
The 20-year-old Super Eagles forward has made a big impression at Anderlecht, scoring seven goals in 14 appearances.
European heavyweights Manchester United and Barcelona are reported to have sent scouts to see him action against Mouscron last weekend.
However, Italian outlet Calciomercato claimed that the Serie A side are now also interested in the star.
The Nigerian striker may also have to make a big decision on his future in the upcoming months.
There hsd been talk of the Toffees recalling him in January as they looked to turn around their fortunes in front of goal.
The forward sparked rumours that he could be set for a comeback after posting a picture on his Instagram account tagging himself in Liverpool city centre last month.
When asked about the picture, he told Belgian newspaper La Libre: “Yes, that’s right and I’m waiting for something. That’s all I can say. I hope to be able to play there in January.
“Everton is happy with my start to the season but we are not in January and all my concentration is in Anderlecht.”
Premier League sides Southampton and Stoke are also interested as well as Dutch giants Ajax and PSV Eindhoven .
Onyekuru recently made his Nigeria debut during a 1-1 draw in the World Cup qualifier with Algeria, and he is a contender to make the squad for Russia 2018