From Halopedia, the Halo wiki
Chol Von's Not Gonna Like This is an achievement in Halo: The Master Chief Collection. It is awarded by killing 1000 skirmishers in the Halo: Reach campaign. It also unlocks the Skirmisher Nameplate.
Skirmishers killed in campaign and custom Firefight count toward the achievement, however kills earned in Firefight matchmaking do not.
Chol Von is a T'vaoan Shipmaster who has aspirations to unite the Kig-Yar and orchestrated a skirmish on the Covenant vessel Pious Inquisitor.