In a bowl or jar (at least 4 cup), mix vinegar, salt, oregano, chili, and 1 3/4 cups water. Combine cabbage, carrot, and onion; add to bowl and push mixture down into liquid.
Cover and chill 4 hours or up to 1 week; mix occasionally to keep vegetables immersed in liquid.
To serve, lift out relish with a slotted spoon and drain.
Nutritional analysis per 1/2 cup.