The Messenger of Allah ﷺ said, "When you sniff water into your nose, do so deeply, unless you are fasting."
حدثنا وكيع حدثنا سفيان عن أبي هاشم
قال رسول الله ﷺ إذا استنشقت فبالغ إلا أن تكون صائما
No references are available.
Its isnad is sahih. Abu Hashim is al-Makki, whose name is Ismail bin Kathir, and he is trustworthy, his hadith being accepted by the group. Asim bin Laqit is also trustworthy. The hadith was reported by Abu Dawud 2/308, no. 2366, Nasai 1/66, no. 87, and Ibn Majah 1/142, no. 407.