。
There's no time to waste.
Literal
Waste [dative-に] do time [topic-は] not-exist.
無駄にする = 'make X go to waste, squander.' 時間 as the direct object of the action, not here marked but implicit in the nominalized expression. The overall sentence has a relative-clause structure: [無駄にする]時間 'time (that one would) waste' → 'time to waste.'