The show has been picked up for season 2 along with Henry Danger Season 3. HD received 20 episodes as cooper posted a video that was shot when wrapped but we are not sure what Game Shakers received. We are guessing the same around 20 episodes as well.
The Thundermans been renewed for another season as well. Bella sadly hasn't been announced yet, but still has a small chance of being renewed. As for 100 Things to do before High School it seems like that show has been canceled. It is very likely that this show won't have a chance being renewed.
All info for new shows and more is listed here http://variety.com/2016/tv/news/2016-tv-upfront-nickelodeon-spongebob-alvinnn-1201720849/