Details and Conditions
I was not able to find an official statement from TinyBuild aside from a 2013 Tweet to a private account.
"@bonestegreat I'm pretty on the fence about it, but yes everyone can make videos of our games and do whatever ya want with em!"
There is also a Steam discussion post by Alex from TinyBuild in regards to the game SpeedRunners. Refer to the DoubleDutch Games section above.
There are no explicit rules against streaming only for paid subscribers on Twitch. I would recommend contacting the developer for certain just in case as an extra precaution.
Keep in mind that TinyBuild Games publishes a lot of different games from many different developers for every platform. You should also refer to the respective developer for each of the example games as a precaution as they may have different policies or conditions.