The proposed £55 million transfer sees the City Ground club agreeing to let Elanga move to the Magpies.
It is a significant deal for both parties, with Elanga having joined Forest in 2023 for £15 million.
Newcastle is strengthening its attacking options ahead of a new Champions League campaign, having already signed winger Antonio Cordero from Malaga without a transfer fee.
Given Newcastle's participation in the Champions League, Elanga is likely to approve the move.
