Can't see why not. The only hurdle is getting familiar with PS Touch's elements (which are a wee bit different than Photoshop's but you already have a head start if you're familiar with the conception of layers).
Another thing: Right now, the max resolution is 1600 x 1600 pixels. Any image brought in will be scaled down to that resolution. (This is a tablet app after all.) I believe you only have so many layers to work with (was it 16? can't remember offhand) so you might have to flatten before continuing on if you import so many images.