SAO PAULO, Aug 31 (Reuters) - Brazilian President Luiz Inacio Lula da Silva and right-wing Senator Flavio Bolsonaro are seen 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, unchanged from an August 24 poll.
In a first-round scenario, Lula would lead with 39% of the votes, followed by Bolsonaro (33%), Augusto Cury (11%), Ronaldo Caiado (5%) and Renan Santos (3%).
The previous poll showed Lula at 41% and Bolsonaro at 37% 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 2,005 people between August 28-30.
The poll has a margin of error of 2 percentage points, greater than the expected difference between the candidates in the second round, a statistical tie.
(Reporting by Isabel Teles)