One of my most anticipated feature for GeForce Experience is the ability to stream on Twitch without using a third party program. Now that's become a reality as an update to GeForce Experience will let you do just that.
Once installed, just go into the Shadowplay area, turn it on, and select the Twitch mode. Use your credentials to login and now you're just a few hot key taps away from streaming on Twitch. There are three quality levels that you can stream at. High quality will need a 3.5Mbps upload speed, medium will need 2Mbps, and low will need just 0.75Mbps.
You'll need a Kepler based card to be able to stream. I've been using Open Broadcaster, but with NVIDIA's implementation, I can now use the power of the H.264 encoding capabilities of the card to do it with, hopefully, little overhead. I'm off to try this out right now.