Basically, get a cardboard or wood box (box size - a bit bigger than the mommy rabbit), pick up the nest with the fur/hay, and put in in the box in the area where the nest was.
Agree with above how are they doing? You want to check on the babies daily to make sure they are alive and well. Mom will not care. Most of us give pets to mom before messing with her kits. She will feed them 1-2 times a day and usually in the early morning or late at night.
Put a box in her cage and pack a lot of hay in it then pound your fist in the hay and make a little burrow in it, but the fur in the nest and put the babies in it they should be fine! If they got cold you can warm them up with a hot water bottle (But be careful the babies could get to hot) or if you have a heating pad you can warm them up a bit that way to but make sure they don't get to hot another way I sometimes like to do it is put them in you shirt but it would be my last choice! I would advise before you touch the babies you should pet the Mum and get her smell on your hands then when she smells her babies she will just smell herself Good Luck keep us posted on how your babies are doing