Mmchk

On April 6, 2026, JYP Entertainment first released a trailer on its social media platforms announcing that Nexz would have a comeback on April 27 called 'Mmchk'. Concept photos of each member and group photos was first posted on April 14. The highlight melody was released on April 17, in which "Mmchk" could first be heard. Music video teasers for "Mmchk" was released on JYP's social media accounts on May 23 and 24.

"Mmchk" lyrics were written by Gu Samyoung, ChaMane and Nexz members Yuki, Hyui and Tomoya. It was composed by Ronny Svendsen, Anne Judith Wik, Heffybeluga, Stian Nyhammer Olsen, Bobii Lewis, JOP and Ameline. "Mmchk" is described as a bass house-based dance track combining playful rapping and an addictive beat. The song shapes around the idea of acting freely without being bound by set manners or outside expectations.

The song is composed in the key E minor and has 120 beats per minute and a running time of 2 minutes and 39 seconds.

Nexz held their first comeback stage for "Mmchk" on Mnet M Countdown on April 30. Nexz also performed on three other music programs in the first week of promotion: Music Bank on May 1 Show! Music Core, on May 2, and SBS's Inkigayo on May 3.