We have no laws to constrain a lame duck president because until now we haven’t needed them. It has been customary for the lame duck president and his administration to cooperate fully with the president elect and his transition team to ensure a smooth transfer of power.
The problem we face now is that Trump doesn’t respect laws or customs. He is having a temper tantrum like a small child because he lost the election. And like a small child, he is breaking everything before he is forced to leave.