You can use almost anything if your design accounts for the mechanical properties of the material. If you have a very flexible material, you would want a short arm on the snap lever. If it's very rigid, then you'd need a longer one to allow the part to flex.

Also, PLA has a very low shrinkage compared to nearly any other material. Every plastic shrinks, PLA is about the least, and you will always need to account for this in your design dimensions.