Yes, as weird as this word looks it is a word. Although it appears to be a compound word I assure you it is not… it is a word that stands alone and is actually a fun word to use.
Chockablock’s first unknown use was during 1850 as a nautical term/ rhyming phrase meaning the two blocks and tactical found on the vessels seaman were work on. [Definition Found HERE]
Now-a-days the word has taken a completely different turn. Chockablock means full, jammed, or overly crowded. This is also believed to be the word that led to the formation of the word chockful (like chockful of information).
Here are some ways of using the word:
I am chockablock of information on weird words.
This room is chockablock of people.