Chalk and chock are easily confused words.
The spell-check application of most word processing software programs would not catch a slip-up of these two words. Spell-check is looking for words that aren’t in its dictionary, and words that resemble words in its dictionary but are possibly spelled wrong. Spell-check isn’t perfect. It doesn’t know and can’t guess what word you wanted or what word you meant, it can only judge the words on the page. If you used words that are all spelled correctly, it gives you a pass anyway.
Autocorrect suggests words that start with the same letters. It’s suggesting what word you may want to save time, but quite often, its suggestions are pretty off base. They don’t help you out, but they do make you laugh.
Chock has multiple meanings. The noun means a wedge or other tool used to take up space to secure a larger, perhaps curvier object in place, like a boat. Chocks are the supports and the metal pieces that hold lines on a dock. Chock the verb means to secure something in place. The word phrase “chock full” describes something filled to capacity, not leaving anything out.
Chalk is a noun. It is molded white (or pastel colored) calcium carbonate sticks used to write on chalkboards or draw on walking surfaces (cement, concrete, pavers). Prior the dry-erase board trend, chalkboards and chalk were common teaching tool in classrooms. Chalk is also part of a phrase, as in “Chalk up”. Chalk up originally meant to score or earn points, which were recorded on a scoreboard. It came to mean a cause and effect relationship: Failing my test can be chalked up to not studying until the night before, and not sleeping well.
The following story uses both words correctly:
Chuck, a server, had several tasks in addition to taking orders and serving food to customers. He wrote the day’s specials in chalk on the main board, and updated it when a dish was sold out. He also regularly walked through the kitchen to make sure the plate chiller was chock full of plates, and other stations had a steady supply of plates and tools. Some servers got “in the weeds” and would forget to do their side work until the end of their shift, but Chuck wasn’t one of those.