Praise be to Allah.
Shaykh ‘Abd al-‘Aziz ibn Baz (may Allah have mercy on him) states that:
“There is nothing wrong with using nasal spray while fasting in cases of necessity, but if it is possible to delay it until night time then that is more on the safe side.” (Majmu’ Fatawa al-Shaykh Ibn Baz (15/264)
In a statement by the Islamic Fiqh Council it says:
“The following things are not regarded as breaking the fast: … eye drops , ear drops , having the ears syringed, nose drops , nasal sprays – if one avoids swallowing anything that reaches the throat.” (Majallat al-Majma’, 10/2/454)
And Allah knows best.