Nurse with a criminal record

It heavily depends on exactly what they were found guilty of/pled guilty to. Saying it wasn't patient/work/substance related isn't really enough detail for anyone to give you a good answer.

What those charges are for will potentially cause issues with her ability to pass a background check most reputable employers would require.  For instance my former employer's policy was any convictions either drug, theft or violence related will cause a potential employee or in rare cases a current employee to fail the background check since they do a new one every year but that's just one employer's policy.

My current employer did a standard background check before I received my official offer letter but has not repeated that since hiring and I've been there a few years so my guess is this company doesn't require ongoing checks after hire.  

Since your wife is currently on probation these are obviously fairly recent charges which could also impact her job hunt. Unless your family is willing and able to pack up and move to a different state I wouldn't bother going too far away for that job hunt without discussing her options with the probation officer as she would need to be cleared to move.

Speaking of probation officer, that person could be an invaluable resource. As long as she is good standing with him/her a letter of reference/recommendation could prove helpful should she get to the point in the hiring process where references are checked.