No, Chaol does not betray Celaena.
Chaol is a loyal and dedicated friend to Celaena throughout the Throne of Glass series. He often puts himself in danger to protect her and always has her best interests at heart. Although their relationship evolves throughout the series, Chaol's commitment to Celaena remains unwavering.
While there are moments where Chaol's actions might seem questionable, they are always rooted in his desire to protect Celaena and ensure her safety. For example, in Heir of Fire, Chaol initially attempts to keep Celaena from participating in the King's competition, believing it to be too dangerous. However, this decision stems from his concern for her well-being and not from any betrayal.
Ultimately, Chaol's actions are driven by his love and loyalty to Celaena. He may not always understand her choices, but he always supports her in the end.