Chips-A-Ho! Cookies are a fictional brand of cookies. They are likely based on the real Chips Ahoy! cookies and likely not using the same name because of copyright reasons.
The cookies appear in "Casa Bonita", while Cartman is trying to fool Butters Stotch into thinking a meteor has turned South Park into a toxic wasteland in order to go to his favorite restaurant, Casa Bonita; along with Kyle Broflovski, Stan Marsh, and Kenny McCormick. Kyle hadn't invited Eric as he owed Butters a birthday invite and Cartman is never even the least bit respectful to Kyle. Cartman locks Butters into a refrigerator to wait out the week while the alleged "monsters" roam the earth in search of flesh. Eric gives Butters a box of the cookies to eat.