Bang Yong Guk - Bangsters (Bang + Gangsters)

Himchan - Hime ("Princess" in Japanese)

Daehyun - Daewons (Combination of Daehyun and WonBin)

Youngjae - Brainboxes

Jongup - Cheetos (Because of his biceps)

Zelo - Jellies

Found these on tumblr. xD Jongup's is the weirdest...