Abu Zuhair al-Anmari (RA) narrated that when the Prophet ﷺ went to bed at night he said;
بِسْمِاللهِ وَضعتُ، اللهم اغفِرْلي زَنْبي وأخْسِى شيطاني و فُك رهاني واجعلني في الندي الاعلى
bismi-l-lâhi wada'tu janbî. ‘Allâhumma-g-firlî danbî, wa'ashi’ šaytânî, wafukka rihânî, wa-j'alnî fi-n-nadiyyi-l-'a'lâ.
“In the Name of Allaah I have laid down my side. O Allaah, forgive me my sin, drive away my devil, free me from my responsibility, and place me in the highest assembly.”
The Supplication which receives an answer
Mâ yuqâlu 'inda-n-nawm (what to say when going to sleep)
253 | pp. 189-190
I have done a new tag page exclusively for the du'ās done by our beloved Nabi Muhammad ﷺ.
Check: Du'ās of Muhammad ﷺ