SAO PAULO, Aug 24 (Reuters) - Brazilian President Luiz Inacio Lula da Silva and right-wing Senator Flavio Bolsonaro are in a technical tie in a potential runoff ahead of October's presidential election, a Nexus poll commissioned by lender BTG Pactual showed on Monday.
In a simulated second-round runoff, Lula would receive 46% of voter support compared with 45% for Bolsonaro.
An August 17 poll had Lula leading Bolsonaro 47%-44%.
In a first-round scenario, Lula would lead with 41% of the votes, followed by Bolsonaro (37%), Ronaldo Caiado (5%), Renan Santos (3%) and Romeu Zema (3%).
The previous poll showed Lula at 41% and Bolsonaro at 36% in the first round.
If no candidate wins more than 50% of valid votes in the first round, the two frontrunners advance to a runoff.
Nexus surveyed 2,006 people between August 21-23; margin of error 2 percentage points.
(Reporting by Isabel Teles; Editing by Gabriel Araujo)