chili vs hot pepper

chili and hot pepper both are nouns.

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

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

chili (noun)	hot pepper (noun)
very hot and finely tapering pepper of special pungency	any of various pungent capsicum fruits
ground beef and chili peppers or chili powder often with tomatoes and kidney beans	plant bearing very hot medium-sized oblong red peppers; grown principally in the Gulf Coast states for production of hot sauce