What does Flexing for Nougat reward?

Flexing for Nougat gives Stormwind Nougat outright.

Where does Flexing for Nougat start?

It was picked up in Stormwind City.

The quest log lists it at level 60.

Yes. Its quest id is not in Classic Era, so it is part of what Forever adds.

World of Warcraft: Forever · quest · level 60 · new since Classic Era

A level 60 quest in World of Warcraft: Forever, offered by a creature in Stormwind City. Recorded by 2 players running the addon.

Giver, pay and objectives show once a player with the addon accepts the quest.

Item	Given	Item level	Vendor sell
Stormwind Nougat	outright	1

What does Flexing for Nougat reward?: Flexing for Nougat gives Stormwind Nougat outright.
Where does Flexing for Nougat start?: It was picked up in Stormwind City.
What level is Flexing for Nougat?: The quest log lists it at level 60.
Is Flexing for Nougat new in WoW Forever?: Yes. Its quest id is not in Classic Era, so it is part of what Forever adds.

What sells at this level, and what to keep from these rewards, is in the level 60 gold guide.

Source: what players running the addon saw in the quest windows; the quest text itself stays in the game. Every quest seen · Stormwind City