The opposite of "chasing away" is "welcoming." Instead of driving someone or something away, one could choose to invite them in or greet them warmly. Other antonyms for "chasing away" include "attracting," "drawing near," or "embracing."
Alternatively, one could simply use the word "approach," which indicates a gathering rather than a scattering. Other related words include "gathering," "assembling," or "forming a crowd."
In short, the opposite of "chasing away" involves the act of coming together, rather than pushing apart. It is an act of collaboration, rather than isolation, and can lead to stronger relationships and a deeper sense of community.