As belivers Christ makes it pretty clear we shouldn't be keeping it to ourselves. His last statement in the Gospel of Matthew is literally
Then Jesus approached and said to them, “All power in heaven and on earth has been given to me. Go, therefore, and make disciples of all nations, baptizing them in the name of the Father, and of the Son, and of the holy Spirit, teaching them to observe all that I have commanded you. And behold, I am with you always, until the end of the age.” Matthew 28:18-20
That nationalism is incompatible with Christianity.