It's a noun phrase. So, it has to be translated to '시간을 낭비하는 것'. Therefore, 'I don't want to waste my time' has to be translated to '나는 시간을 낭비하는 것을 원하지 않는다.'in literally. And liberal translation is '나는 시간을 낭비하고 싶지 않다.' And both of literal and liberal sentences that I wrote above are quite natural.