Chester Anton Mathias Hansen is a Canadian musician and songwriter, best known as bassist of instrumental group BADBADNOTGOOD. As a Grammy Award-winning songwriter, Hansen often works with his bandmates and producer Frank Dukes and is credited for co-writing hit songs by Drake, Kendrick Lamar, Daniel Caesar, and Kali Uchis, among others.

BadBadNotGood is a Canadian instrumental band and production team from Toronto, Canada. The group was founded in 2010 by bassist Chester Hansen, keyboardist Matthew Tavares, and drummer Alexander Sowinski. In 2016, they were joined by frequent collaborator Leland Whitty. Among other projects, the group has released five solo studio albums, with the latest, Talk Memory, released in October 2021. They have had critical and crossover success, finding audiences in the hip hop, jazz, and alternative music communities.