So far, these are the wrestlers that have been confirmed 
by THQ (the developers of WCW/NWO Revenge):

Kevin Nash 

Sting 

Lex Luger 

Randy Savage 

Curt Hennig 

Hollywood Hogan 

Bret Hart 

Giant 

Scott Steiner 

Scott Norton 

Raven 

Diamond Dallas Page 

Booker T 

Chris Benoit 

Chris Jericho 

Eddy Guerrero 

Rey Mysterio, Jr. 

Disco Inferno 

Dean Malenko 

Ultimo Dragon 

La Parka 

Lodi 

Konnan 

British Bulldog 

Goldberg 

The following wrestlers are very, very likely to be in the game: 

Scott Hall 

Juventud Guerrera 

Chavo Guerrero, Jr. 

Reese 

Fit Finley 

Jim Neidhart 

Stevie Ray 

Glacier 

Kanyon 

Saturn 

Mongo McMichael

Kidman 

Brian Adams 

And lastly, these wrestlers are "maybes": 

The Ultimate Warrior 

Rick Steiner 

Buff Bagwell

 BaCk