Does Chika have a side effect?
Yes, at least in the anime Chika Amatori has a side effect.  This is shown is episode 6 which was called "Chika Amatori's Side Effect".  Her side effect appears to be at least the ability to sense neighbors searching for her with hostel intent. Note: all sensory improvements due to high amounts of Trion are called side effects and no one so far seems to have the same ones.