chess player vs participant

chess player and participant both are nouns.

Word	Noun	Adjective	Verb	Adverb
chess player	Yes	No	No	No
participant	Yes	No	No	No

As nouns, participant is a hypernym of chess player; that is, participant is a word with a broader meaning than chess player:

Other hypernyms of chess player include player.

chess player (noun)	participant (noun)
someone who plays the game of chess	someone who takes part in an activity
	a person who participates in or is skilled at some game