Assalaamu alaykum wa rahmatullaahi wa barakaatuhu. Can I read Ayat Al-Kursi before sleeping in the daytime?

All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallahu ‘alayhi wa sallam, is His slave and Messenger.

You may read Aayat Al-Kursi before sleeping in daytime. Shaykh Ibn ‘Uthaymeen was asked, "If a person wishes to sleep at noon, can he recite the reported Thikr (expressions of remembrance of Allah), or is reciting it confined to before sleeping at night?"

He replied, "I seems to me that the reported Thikr should be recited before sleeping at night. However, there is no harm if the person recites it before sleeping in the daytime because it is Thikr and because there is no explicit text indicating that the Prophet, sallallahu ‘alayhi wa sallam, only recited it before sleeping at night." [Fataawa Liqaa' Al-Baab Al-Maftooh]

Allah knows best.