What are the differences between "Nirvana" in Buddhism and "Moksha" in Hinduism?

Concept of Moksha is more analogues to birth in a higher plain of existence as per Buddhist Cosmology. E.g. merge with God. Nirvana is to get out of the cycle of birth. The Moksha concept is that you achive the same when you merge with god.

The original answer saying that attaining personal wealth and mastery of sex is important for moksha is completely, 100% wrong and as a hindu I am extremely offended. Moksha and Nirvana are connected and the buddhist concept basically branches from the hindu concept of Moksha. Please please do not spread wrong knowledge about our religion. Moksha is a way to be one with the God and remove yourself from the cycle of rebirth. It is essentially what nirvana is.

Enlightenment like ice cream comes in different flavors, but in the end they are all ice cream, made from milk, cream and sugar.

Examined with the intellect there are a lot of seeming differences, even within a single religion's idea of enlightenment - Bodhisattva or Arhat? Japanese Zen or Thai Theravada? Realizing the Atman or becoming a deva?

Examined with pure awareness where one loses the egotic sense of self, there is no difference, all paths lead here - but this is rarely said because it is impossible to explain this view in words.

‘Emptiness’, after all, is not an idea to be grasped: it is a provocation, a literal insult to the intelligence

In any case in his discourse on Simsappa leaves the Buddha says such questions are not answered by him, because they don't solve the problem of suffering.

The personal enlightenment model of Buddhism says the Arhat is liberated from further becoming, but this doesn't mean annihilation, neither is it further existence. Arhats and Buddhas are said to guide others to enlightenment after their bodily death too by appearing in dreams and visions of aspirants, and hence the existence of Reliquaries to them.

The Tatagatha (i.e. Buddha) never answers this question: SN 44.6 - Does the Tathagata exist after death?.

The Bodhisattva belief is that personal enlightenment is not possible until all beings are liberated.

See Arahants, Bodhisattvas, and Buddhas by Ven. Bhikkhu Bodhi

These two ideals may appear contradictory, but they are all compatible and become indistinct eventually.

So too with Hinduism vs Buddhism.

Both Buddhism and Hinduism agree that there is no end to the cycle of life per se, the universe or multiverse is created and destroyed perpetually despite all the many Arhats and Bodhisattvas, because they don't leave the system. See Aggañña Sutta

Hindus are not a single people, there are numerous ideas that all make one Hindu, since it is a Western classification of religion in the Indian subcontinent. Following this "dharmic" ideal, in Indian law there are no Buddhists or Jains in the Constitution, there are only those who follow Indian religions (Sikhs, Buddhists, Jains, various kinds of animistic and vedic traditions commonly called Hindus) all referred to as Hindus (of India), and non Indian religions such as Christianity.

In fact, the Buddha is seen by many Hindus as an avatar of Vishnu.

Buddha statues sit side by side with Hindu gods in prayer rooms in homes in India, and Ganesha jostles with Buddha in Thailand, a Buddhist country.

In any event, Hinduism and Buddhism are not an Orthodoxy but an Orthopraxy.

There is no correct belief, only correct action.

There is no Hindu or Buddhist Pope who can lay down the law. Popularly though, it is common for Buddhists to believe Hindus are orthodox with rites and rituals.

Arhats and Bodhisattvas are not at war with creation, they are a part of creation, just as much as Samsara. There can be no left side without the right side, there can be no Nirvana without Samsara.

The Zen movement in Japan is especially fascinated with this, a radical immersion in samsara because it is no different from Nirvana - It becomes less true to say that ‘an individual has experiences’ than that ‘experience has individuals’.

To say there is enlightenment is a lie, but to say there is no enlightenment is a bigger lie.