That's definitely a nest.
When it comes to nests tho, just remember, it's not the size of the ship but the motion of the ocean. lol
I've had Bettas make nests that were the size of a dime to almost covering an entire 2 1/2 gal tank. Size doesn't matter. What matters is how many viable eggs he puts in the nest. In one of my recent spawns, the male first put all the eggs in the nest then, once I removed the female, lined each egg up in a single line along the side of the tank without any other bubbles. The original nest was still in tact. Like I said, nest size doesn't matter.
Here's a hint for you styro cup breeders, I use a piece of fresh Romain lettuce for my males to make nests under. It stays in pretty good shape if you make sure you have both sides of the stalk. By the time the fry hatch and become free swimming, there is a dose of infusoria for the smaller babies to feed on while I start feeding Newly hatched brine shrimp. Works like a charm, every time.