This letter is from Paul, chosen by the will of God to be an apostle of Christ Jesus. [Colossians 1:1]
In my church background, talk about being “chosen by God” was primarily a debate about whether we are ‘saved’ because God chose us or because we chose God.
Otherwise known as the doctrine of election or predestination.
In the reformed tradition we have a whole document(“The Canons of Dordt”) dedicated to explaining that the right answer is that God chose us, and everyone who teaches otherwise is wrong!
I have studied this debate, and participated in it, for years; I know the bible verses usually brought up by both sides.
My own perspective is in the mysterious middle – God chooses us and we choose God, and somehow it all works out.

But what is missing in this abstract theological debate is the purpose for which those that are chosen are called.
What does it mean that God chooses us, or that we choose God?
Think about the army: whether we are conscripted or we sign up voluntarily, we are there for a purpose.
I see the issue of being “chosen by God” less a matter of privilege (‘I am chosen, you are not’) and more a matter of responsibility!
What we need to figure out most of all is what it is we are chosen for.
According to Paul, it is to be an apostle (or missionary) of/for Christ Jesus.

When we talk about being “chosen by God”, don’t forget that we are chosen for a purpose!
If only we had a whole document in our tradition dedicated to explaining this!!!