The thing about clearing waves is you either rush a nashor's or a protobelt. I don't think Nami mid is GREAT but I think it can work. I would try to do an E max with a nashor's but if they have really good waveclear maybe rush a protobelt.
You could probably play her top and get away with it because of her ult and CC(You'd only really use your ult to either keep someone from escaping or to get away yourself so it could be really nice to be able to hold on to that for yourself) and not to mention most top laners can't push super hard.