Hi @Tess,
I don't remember what I tried to do 
I think I tried to add "NOVALUE" in the array returned by the query through JS.
What I was trying to do it's not adding the input value if not exists, but add a specific value (eg. NOVALUE) for any input that doesn't exists in the list.
So, based on your example, "Nik" should return "Nike" options and NOVALUE at the end.
At the moment, I solved adding "NOVALUE" in first position with an UNION ALL in sql query and, if you want to select it when no results, you select it from the list in first position or using the search.
Thanks