Zhè shì wǒ dàxué shíhou yòng de wǎngmíng, tǔ sǐ le.
This is the username I used in college — it's incredibly cringey.
Tips
usage
Generic, used across all platforms. For platform-specific terms: 微信名 (WeChat name), 抖音号 (Douyin ID), 用户名 (yònghùmíng, formal 'username' in registration forms), 昵称 (nìchēng, 'nickname' in app UI menus).
culture
Chinese 网名 culture loves quirky/poetic nicknames over real names — 一只小猫咪 ('a little cat'), 月光下的猫 ('cat in moonlight'), 夏目友人帐 (anime references). Real-name display is required for verification (实名 shímíng) but most platforms still let you display a 网名 publicly.