It can be translated with May God bless you, but it can also be used as an exclamation when the person is very much suprised by what he/she sees, hears etc.
Examples:
Bog te video, kolika guzva-Oh my God, such a big crowd (you are suprised by the fact that there are so many people in some place.)
Bog te video, kakav nered-Oh my God, what a mass!
I supposed you've heard this expression in the name of the film "Montevideo, Bog te video" and hear I believe the meaning is this one, their dream about going to the championship came true and they can not believe it so one of them says "Montevideo, Bog te video" Montevideo, I can't believe it!!! Although the movie is translated as The taste of a dream.