One would assume the match would be conducted under rules similar to the old War Games: The Match Beyond. The Chamber was actually created after Triple H pitched using the Wargames double ring cage structure, only to have the idea shot down and the Chamber created instead.
In a comment this afternoon, Ryback alluded to the addition of the Chamber on Twitter, writing, "Justice will be delivered hard to @theshieldwwe this sunday in NOLA in The Chamber. #FeedMeMore"
Ryback's comment is the first time the match has been described as being "in the Chamber", so we will see.
Thanks to Marco for his help.