Since some context has been omitted, we will assume that the car being referenced is directly before the speaker and listener, making 'this' the relevant adjective for purposes of translation.
Also omitted is the noun (kuruma) following 'no' in the first sentence and the topic in the second sentence. While this is completely natural, especially in spoken Japanese, when formulating a 'complete sentence' and when translating, what is omitted should still be considered.
A. (Kono) kuruma wa dare no (kuruma) desu ka? (This) Car is whose (car)?
B. (Kore wa / Kono kuruma wa) Dare no kuruma desu ka? (This / This car is) Whose car?
If we look at both 'completed' sentences above we can see that they are saying the exact same thing, namely: Kono kuruma wa dare no kuruma desu ka? What has been omitted for the sake of brevity, naturalness, politeness, or personal preference is what makes them different. I wouldn't say that there is any real difference in nuance.
B seems far more casual/colloquial to me, for it contains the necessary elements for comprehension while being more compact/brief.
I would translate either as 'Whose car is this?'.