Added Married Mom only to property husband and I are purchasing

The details and alignments are a bit unclear.  However, the simple answer is have mom quit-claim the property back to you -- it will not change the mortgage obligations in any way, but will remove her, and therefore any potential derivative direct claim by her husband -- against you or the property.  If (as is likely) the situation is actually more complicated, your best bet is to confer with a knowledgeable family law specialist.  For a basic explanation of how marital property claims work in Nevada, see here.