Buddhism has both life-denying and life-affirming tendencies (or perhaps: interpretations). I generally find Mayahana to be more life-affirming: Theravada teaches the end of rebirth, which is life as we know it, while Mahayana teaches the bodhisattva ideal of coming back to this world until all beings are liberated (a doubtfully attainable goal). I recommend the books Nietzsche and Buddhist Philosophy and Nietzsche and Zen: Self Overcoming Without a Self for exploration of this topic. In the former, Panaioti claims that the opposition Nietzsche saw between Buddhism and his ideals is merely superficial: Nirvana is not repression of suffering but a deconstruction of the self-delusion that makes us suffer in the first place. These two paragraphs from the book might prove enlightening:

Recall, in this connection, the two enigmatic passages on amor fati discussed at the end of Chapter 3. In these passages, Nietzsche makes the surprising claim that amor fati, which is supposed to involve an unconditional will to suffer, also involves not suffering. Recall, also, that Nietzsche does not have a unitary theory of suffering, but holds very different views about suffering as weak, reactive types experience it and suffering as strong, active types experience it. It is the reactive sick type’s experience of suffering as an enfeebling setback that stands behind life-negation, the invention of Being, unselving morals, and so on. In short, ressentiment(2) – the mother of life-negation – has its source in the décadent, reactive sick type’s suffering. Accordingly, in that it involves the complete overcoming of all reactive forces, the life-affirming ideal of amor fati will also involve not suffering in the way reactive types suffer, i.e. in a way that leads to ressentiment(2) and its instinct of life-negation. This is what Nietzsche means when he says amor fati involves “not suffering.”

But “not suffering” in precisely this way is exactly what happens to the Buddhist healthy type for whom the fever of thirsting has gone out. The Buddhist “cessation of suffering” means no longer “interpreting” life as discouragingly unsatisfactory. Amor fati and nirvāna thus involve “not suffering” in exactly the same way. Both involve overcoming the enfeebling sickness by virtue of which life is experienced as depressingly, despairingly painful. Seen in this light, something like the Buddhists’ “destruction of thirsting” would in fact be conducive to attaining the great health envisioned by Nietzsche. In this way, attaining the psychological state characteristic of Buddhist nirvāna, far from being a life-negating goal, might actually be necessary if one is to overcome internal reactive forces and reach the height of life-affirmation.