My experience has been using wooden nestboxes but will touch on metal nestboxes as well. Rule #1, whether building your own or buying ready-made nestboxes, measure the cage door so you know it will fit thru the cage door. Don’t laugh, it has happened to a few folks out there! Make sure that once the nestbox is inside, there is still room for a doe to lie down comfortably.
A good size nestbox for a HL doe is 8 ½” wide x 15” long x 8 ½” high at the back end gradually going down to 5” high at the front end. Wood that is ¾ inch thick is nice. Do not use walnut or other toxic or treated wood. Make sure the edges are sanded and even better are those sanded into a curve instead of straight edge. I find the rabbits tend to chew less on a curved edge, maybe it is harder to get their teeth around it? You might want to add a sort of 2” lip on the inside front to keep babies in if they hang onto the mom when she exits the box. Have 8-10 “ventilation holes” drilled into the bottom. Another option is a removable insert bottom. If the sides get chewed down, at least you have the bottoms when you toss the rest.
You can disinfect the nestboxes with a bleach/water combo or Lysol and then set them in the sun to dry.
Metal nestboxes have the advantage being virtually indestructible, not getting chewed up like wooden ones. Other advantages are easier disinfecting and much quicker drying time as you can just wipe them dry. Though I would still try to sun-dry them for the added germ killing effect. The metal nestboxes have wooden inserts or heavy cardboard can be used. I’ve heard of layers of newspaper and cardboard being used inside for insulating during cooler temps. Living in the Northeast, metal wouldn’t be an attractive alternative to me.