The word "Chesteyn" is spelled with a combination of consonants and vowels. The letter "C" is pronounced as /tʃ/ and followed by "h" which produces the /h/ sound. The letters "e" and "y" indicate the long /eɪ/ vowel sound. The letter "s" is pronounced as /s/ and "t" is pronounced as /t/. Finally, the letters "e" and "n" indicate the ending syllable which is pronounced as /ən/. Therefore, the correct IPA phonetic transcription of the word "Chesteyn" is /tʃɛsteɪn/.