Final answer:
The Moscatel grape is used in Setubal, Portugal, to make sweet, fortified wines known as vins doux naturals.
Step-by-step explanation:
The grape used in Setubal, southwestern Portugal, for making vins doux naturals is Moscatel, also known as Muscat. This grape variety is renowned for its sweet, fortified wines, which have a rich history and distinct character tied closely to the region's climate and terroir. The Moscatel wines of Setubal are highly appreciated for their unique floral aromas and complexity.