The 30-year-old scored on his return to St James' Park to claim all three points for the Hammers, helping them into sixth place.
"That's five he's got now and the enormity of Kevin's goal record for us means he's our top scorer," Allardyce told Sky Sports News. "Our frontmen are not really scoring at the minute but we're sharing the goals out.
"The way he played off Andy [Carroll] is what I liked the most. He really does sustain the attacks by holding the possession up.
"He read the situation well in the box. It's a tap-in but you've got to be there and Kevin always seems to get in the box at the right time."
Nolan left the Magpies to join West Ham in 2011.