I would recommend against that, but maybe for very very light usage it would be tolerable. Video conversion and encryption will be very very slow on that processor.
I don't have fist hand experience, but I would suspect that trying to decrypt a video a video file and stream it in real time would be difficult for that cpu.
Oneprovider's next step up for dedicated server has the Atom c2750 which is literally 10 times more powerful, and has 8 cores instead of one. Cost is double, but 15/month isn't a lot and the machine will do everything you want very comfortably. Plus it has a 1TB drive. 160gb will fill up quickly with hd video. You won't feel the need to upgrade if you go that route, and won't have to go through the trouble of reconfiguring everything again if the nano is too weak for your usage.
My only complaint about my OP server is that it's in Paris and I'm in San Francisco - I sometimes have trouble streaming high bitrate hd video when the networks are congested.