If she filed for guardianship, has a court heard arguments on any temporary orders?

Further, it appears that pursuant to NRS 200-359 if she fears for the imminent safety of the child and reports this to child welfare services or the police she can be exempt from prosecution. Assuming she has complied with the law by making these notifications and then filing for guardianship, you may have to proceed through the court process. I doubt that a court would keep the child from her mother absent SOME credible evidence of abuse or neglect - not just your mother's word on it.

I would recommend you consult a Family Law attorney ASAP.