Nascimento, who was a late replacement for durable veteran Sherman Williams, brought a 17-5 record to the contest, which was largely padded by results in his homeland.
Parker dropped the 1.96m Brazilian with a stinging right hook late in the first round and Nascimento was given the count but managed to get to his feet in time.
In the second, Parker continued his plan to work the body as he delivered a few powerful strikes and looked to wind up his right hook.
He wasn't able to land a killer blow but took the round as he continued to assert his dominance in the bout at a sold-out Konig Pilsener Arena.
Parker continued to chase his opponent around the ring in the third as Nascimento looked laboured and left his chin on display.
Nascimento's chin proved durable during the fourth though as he ate a heavy left hook from Parker late in the round but the Brazilian continued to hold on as Parker moved ahead on the scorecards.
In the fifth, Nascimento landed a couple of strong shots but Parker still took the round, although the Brazilian found his range in the sixth.
He opened Parker up with a cut above his left eye, which was the same spot he was badly cut during his bout with Tatupu while a big shot to the side of his head stunned the South Aucklander.
The young Kiwi looked dazed on his feet as he became sloppy with his jab and looked to land a heavy finish rather than continue to work.
But in the seventh, which turned out to be the final frame, Parker's power began to show and when Nascimento was unable to defend himself the bout was stopped.
Considering the global audience and the magnitude of the impending world title bout, it was a decent showing from Parker, who notably stuck to his team's directions during the fight.
His ability to work the body and remain active through a majority of the fight would have pleased trainer Kevin Barry.
Parker is scheduled to fight again in Auckland in July with his opponent to be announced shortly.
- Daniel Richardson travelled to Germany courtesy of Duco Events Ltd
