While West Ham can go top of the Championship with a favourable result, Forest are aiming somehow to recover from their FA Cup mauling at Leicester.
Allardyce however was in attendance at the King Power Stadium and told www.whufc.com that the game was closer than the scoreline may have suggested.
"At half-time it should have been 2-2. They had two of the best chances in the game and didn't convert them.
"Eventually they will convert them but we want to make sure it is not against us."
The reverse fixture in August resulted in a comfortable 4-1 win for the Hammers at the City Ground.