Mishna Berura 471:2:12 says there are those that do not eat Matza starting Rosh Chodesh Nissan. May one eat Matza that is Chometz?
In OC 471 sk 12, the Mishna Berurah mentions that certain types of matza which we are only machmir to treat as chametz (eg matza that folded over itself in the oven) are forbidden to be eaten on Erev Pesach as they are actually kosher matza according to the basic law. The assumption of this point is that had they actually been chametz, they would have been permitted despite tasting exactly like matza. So your chametz-crackers are permitted.
EDIT: In his footnotes to the Mishna Berura (published as ביצחק יקרא), Rav Nevenzhal says that the matza sold year round as chametz should not be eaten on Erev Pesach even before the fourth hour as it might actually be kosher matza and therefore forbbidden. He does not mention if this chumra (that it might not be chametz) applies going back to Rosh Chodesh, or only on Erev Pesach when the possible prohibition is rabbinic in nature.