I see a lot of stuff that sort of show that Jainism is related to Hinduism.For example, Was Parsvanatha, the 23rd tirthankara of Jainism, an avatar of Lord Shiva? Asks if Parsvanath, the 23rd tirthankara of Jainism was an avatar of Lord Shiva.
Better question to ask would be 'Is Jainism related to Hinduism' ?
because Jainism came later.
Yes, it is related.
Jainism falls under Nastika school of thought because they don't accept the authority of Vedas.