The Brazilian, who is now a regular driver in NASCAR's Camping World Truck Series, notched a victory in just his third Nationwide start.
He finished 2.26 seconds ahead of Michael McDowell on the 4.048-mile, 14-turn Wisconsin road course.
The 26-year-old son of three-time F1 world champion Nelson Piquet started on the pole and led for 19 of the event's 50 laps, becoming the fifth foreign-born driver to win a Nationwide Series race this year.
Claiming third place was Ron Fellows, while Italy's Max Papis and Sam Hornish Jr. rounded out the Top 5.
Elliott Sadler settled for 15th place but retained his points lead, posting an 11-point advantage over 18th-place finisher Austin Dillon.