Your energy use is going to be much more impacted by how full you keep your freezer. For the same reason.. the more product you have in there, the less air you have in there.

Your chest freezer will typically use about the same about of yearly kWh as a standing freezer would, but the chest freezer will typically have about 30% more capacity.

So.. it's "better," but if you're not going to keep it full, you may not actually be saving any total energy.