CHALKS is a playable word

chalk Scrabble® Dictionary

verb
chalked, chalking, chalks
to mark with chalk (a soft limestone)
40 Playable Words can be made from "CHALKS"
   2-Letter Words (7 found)
   3-Letter Words (14 found)
   4-Letter Words (10 found)
   5-Letter Words (8 found)
   6-Letter Words (1 found)