Brandao scored twice as St Etienne blew struggling Nancy away inside the first 25 minutes at the Stade Geoffroy-Guichard.
The former Marseille man's double was added to by Romain Hamouma and Pierre-Emerick Aubameyang in a stunning early onslaught.
Nancy lost Simon Zenke to a red card in the second half and the hosts could have had even more goals in a convincing win which lifted them to seventh in the Ligue 1 table overnight.
Nancy went into the game having not scored a league goal in over 500 minutes but they hit the post after only seven tonight, Benjamin Moukandjo the unlucky party as Stephane Ruffier got the slightest of touches to his powerful strike.
But they were behind only two minutes later as Jonathan Brison curled the ball in from the right wing and Brandao climbed highest to head home his first goal of the season.
It was 2-0 with 19 minutes on the clock when Renaud Cohade swung the ball in from the left channel for Hamouma to head home.
Brandao made it 3-0 just two minutes later with yet another header, the Brazilian finding space to meet Aubameyang's right-wing cross and score his second of the night.
And Aubameyang added his own name to the scoresheet in the 25th minute after racing on to Cohade's long pass and clipping the ball deftly over beleaguered keeper Damien Gregorini.
Andre Luiz, outpaced by Aubameyang for that goal, almost made some amends when his downward header forced a good save from Ruffier.
But St Etienne's Josua Guilavogui hit the post just before half-time and was inches wide with a 20-yard strike early in the second half.
Ruffier denied Loosemy Karaboue after a fine run and shot midway through the second half but Nancy were almost immediately reduced to 10 men, Zenke dispatched to the dressing room after a wild lunge over the top of the ball on Faouzi Ghoulam.
Hamouma almost added a cheeky fifth goal in the 82nd minute, but Gregorini was alert to his backheel from Max Gradel's cross.