Does Chika have a side effect? I recently started World Trigger and I was wondering if Chika Amatori has a side effect. It seems that she is able to sense the presence of Neighbors before they come through a portal. Does this count as a side effect or is it just something that people with high amounts of Trion already have?
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.