I live in an area with a large chunk of Indians, and a significant chunk of Nepalis. Of the Nepalis I've met, a large chunk of them have been Hindu and Buddhist syncretists. Of the Hindus I've met, a large chunk believe Buddha to be an incarnation of God.
From Wikipedia:
Gautama Buddha in Hinduism - Wikipedia, the free encyclopedia
Harivamsha (1.41)
Vishnu Purana (3.18)
Bhagavata Purana (1.3.24, 2.7.37, 11.4.23)
Garuda Purana (1.1, 2.30.37, 3.15.26)
Agni Purana (16)
Narada Purana (2.72)
Linga Purana (2.71)
Padma Purana (3.252) etc.
However, it seems there are two or three Buddhas spoken of: the son of Śuddhodhana, whom from Buddhism we can guess is Siddhartha Gautama Buddha the Shakyamuni. However, there is also the son of Jina, and Añjana.
Unless these are merely other names that Śuddhodhana was referred to by others or incorrect choices in names for some reason, we may have different people mentioned.
Not to mention, Buddha calls himself Vishnu (and everything else) in the Laṅkāvatāra Sūtra. Long-winded quote, but cut short:
"Of these, Mahāmati, some recognise me as the Tathagata, some as the Self-existent One, some as Leader, as Vinayaka (Remover), as Pariṇāyaka (Guide), as Buddha, as Rishi (Ascetic), as Bull-king, as Brahma, as
Vishṇu, as Īśvara, as Original Source (pradhāna), as Kapila, as Bhūtānta (End of Reality), as Arishṭa, as Nemina, as Soma (moon), as the Sun, as Rāma, as Vyāsa, as Śuka, as Indra, as Balin, as Varuṇa, as is known to some". - trans. by Daisetz. Teitaro Suzuki.
Make of it what you will.