stuff vs chock up

stuff is a noun but chock up is not a noun.

Word	Noun	Adjective	Verb	Adverb
stuff	Yes	No	Yes	No
chock up	No	No	Yes	No

As verbs, chock up is a hyponym of stuff; that is, chock up is a word with a more specific, narrower meaning than stuff:

Other hyponyms of stuff include cram, jam, jampack, ram, wad, overstuff, fill out, pad.

stuff (noun)	chock up (noun)
miscellaneous unspecified objects
unspecified qualities required to do or be something
a critically important or characteristic component
senseless talk
information in some unspecified form
informal terms for personal possessions
the tangible substance that goes into the makeup of a physical object

stuff (verb)	chock up (verb)
fill with a stuffing while cooking	crowd or pack to capacity
fill tightly with a material
treat with grease, fill, and prepare for mounting
overeat or eat immodestly; make a pig of oneself
cram into a cavity
obstruct
press or force