Chins are smart!
You might think about Plexiglas ... not right up against the cage (that would cut off needed air flow and give your chin something else to chew on), and not attached to your wall. You want to be able to remove it to clean it weekly.
If you get 2 "U" shaped brackets (distance between sides of the "U" bracket should be about 3 inches) and bolts ... attach one side of the "U" (upside down) to the Plexiglas (drill the holes for the 2 screws in each U bolt) and the other side can be hooked in the top of the cage by dropping the other side of the "U" bracket into the top of the cage.
With a 2 story cage, you may want to use 2 more brackets that are "L" shaped. The L shaped brackets would be attached to the bottom of the Plexiglas and the other side of the L bracket slid under the bottom of the cage. This is a little more tricky ... you may have to hook the top bracket with the Plexiglas at an angle, then slide the L bracket under the cage or as a spacer to hold the Plexiglas at the bottom away from the bottom of the cage. Exact measurements is a must here.
Always place the Plexiglas side of the cage up against the wall ... otherwise the extra weight might tip over the cage.
Caution: When using the L brackets make sure the brackets will not be scratching the surface of your furniture. If your chin's cage sits on a good piece of furnature, do not use the bottom brackets under the cage.
Jo Ann
PS A hot glue gun is good for making your own lower brackets/spacers out of the Plexiglas if you do not want to use metal brackets at the bottom of the cage or can not find the ones you need. Two or three pieces about 3" (or same size as the width between the U brackets) wide can be hot glued to the bottom of the Plexiglas to make your spacers at the bottom of the Plexiglas.