Chaoticnightcore is a personal aesthetic about big friend groups doing chaotic activities at night. This can be, for example, going to a party, playing music in the car with the windows down, going to an abandoned playground, or just hanging out at night in the middle of nowhere.
A photo example.
Mainly you see photos of it on TikTok and Pinterest. Usually, when making these photos, people will put a speed motion filter on it.