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Being in Brazil without a residence permit is not the dead end it would be in most countries. Brazilian law says in terms that a residence permit may be granted regardless of your immigration situation — so having overstayed or entered without the right visa does not, by itself, shut the door.
What it does mean is that the naturalisation clock has not started. Residence time counts from lawful residence, so the work is to regularise first, on whichever ground fits — family, work, investment, a pension, or a treaty if you are a South American national — and then let the years run. A late application can attract an administrative penalty, which is a sanction rather than a bar to the permit.
Once regularised, the wait is four years in the ordinary case, or one year if you have a Brazilian spouse or partner or a Brazilian child, or hold the nationality of a Portuguese-speaking country.
Every naturalisation route also asks for three things we have not asked you about: civil capacity, no criminal conviction (or rehabilitation), and enough Portuguese to communicate — judged against your circumstances, not by examination, and with allowance made for disability.
Tell us how you came to be in Brazil, how long you have been there, and what family or work ties you have, and we will tell you which ground to regularise on.