chili pepper vs hot pepper

chili pepper and hot pepper both are nouns.

Word	Noun	Adjective	Verb	Adverb
chili pepper	Yes	No	No	No
hot pepper	Yes	No	No	No

As nouns, hot pepper is a hypernym of chili pepper; that is, hot pepper is a word with a broader meaning than chili pepper:

chili pepper (noun)	hot pepper (noun)
very hot and finely tapering pepper of special pungency	any of various pungent capsicum fruits
plant bearing very hot and finely tapering long peppers; usually red	plant bearing very hot medium-sized oblong red peppers; grown principally in the Gulf Coast states for production of hot sauce