Carried out by Spinter Tyrimai, the survey shows that 17.2 percent of the country's population would vote for Grybauskaite, and 15.6 percent would give their votes to Nauseda.
Incumbent Prime Minister Ingrida Simonyte comes in third with 8.4 percent, followed by Ignas Vegele, ex-chairman of the Lithuanian Bar Association, with 6 percent, and ex-Prime Minister Saulius Skvernelis with 5.6 percent.
Further down the line are journalist and public figure Andrius Tapinas with 3.7 percent, Vilija Blinkeviciute, leader of the opposition Social Democratic Party of Lithuania, with 3.4 percent, Defense Minister Arvydas Anusauskas with 3.2 percent, Ramunas Karbauskis, leader of the opposition Lithuanian Farmers and Greens Union, with 2.7 percent, Aurelijus Veryga, a Farmers and Greens MP, with 2.3 percent, Speaker of the Seimas Viktorija Cmilyte-Nielsen with 2.2 percent, and Foreign Minister Gabrielius Landsbergis, leader of the ruling Homeland Union - Lithuanian Christian Democrats, with 2 percent.
Other candidates would receive less than 2 percent of votes, and another 5 percent would vote for some other candidate.
Meanwhile, 9 percent would not vote at all, and another 13.7 percent were undecided.
During the survey, respondents had to choose their favorites from a provided list.
The next presidential election in Lithuania will take place in the spring of 2024.
The Spinter/Delfi survey of 1,015 people was carried out between August 25 and September 2. The margin of error is 3.1 percent.