I was going to post the same question, as it sure seems odd. So, I googled it and this was the best explanation I found:
It's a longboard, those things are super buoyant. Additionally certain boards are specifically shaped for nose riding, things like wider nose for more buoyancy up front and a rounded bottom.
More specifically you'll notice you don't see noseriding while the surfer is perpendicular to the wave but rather more parallel. Thus while the front of the board looks very out of the water, they have the rails of the surfboard on the side closest to the wave dug into the water relatively far up, thus giving a lot of resistance to their weight. Meanwhile the tail of the board will either be unweighted (sort of like a skateboard nose manual, but not so dramatic), acting a bit like you're riding a shorter board. Combined with the slope of the wave and the rushing water underneath the nose, it prevents diving (you are technically diving, but the curve of the wave and your forward momentum keeps catching you). Or the tail will actually be dug into the water partly submerged (usually under the curl of the water), giving resistance against being pulled upwards.
https://www.reddit.com/r/explainlikeimfive/comments/352s9r/eli5_how_does_hanging_ten_on_a_surfboard_work/
Maybe this helps illustrate?
