Is my divorce im Mexico valid, how do i register it in the courts in NV?

It is unclear what you are trying to accomplish.  There is no legal need to "register" a divorce elsewhere in Nevada unless/until you are attempting to do something relating to status in Nevada.  Presuming there is some reason to do so, you could register the Decree under the USFSPA if there are custody issues, or under UIFSA if there are support issues, or simply domesticate it under the old statute if there are no child-issues.  It is probably a good idea to confer with a family law specialist before doing any of those things to make sure there is a need to do anything at all.