Love the stretch cruiser look! But there could be a couple problems.
I assume NX3 means it has an internally geared hub, and that's why you chose a front hub motor. Seems like the right move, but there are a couple things you might want to consider.
I don't know anything about that fork, but I doubt it's up to the task of holding a Magic Pie. A Magic Pie is a big, heavy motor, and it'd be tough on any suspension fork, let alone a flexy springer fork. Swapping a fork is easy to do though.
Also, if you're planning on running at anything close to fun speeds, you'll want a front brake. If you get a new fork, maybe you can get one with a disk brake mount. Rim brakes might be ok, but with that much weight spinning in a front wheel, I'd personally opt for disk.
Maybe someone else can comment on the feasibility of using a small, geared, hub motor on a springer fork or maybe a mid-drive.