maybe your AC/room collecting dust? try to service and clean your room first and see if any different.
i know coz my wife also having same

It’s probably something in your diet. I too sometimes have partial nose block and I immediately know it has to be something I ate earlier in the day. By next morning, I feel okay again.

Nose gets blocked cos in the nasal cavity in the skull is filled with mucous.  There is something that has made ur polyps inflamed and it’s secreting mucous and the nose closes so I don’t get the drips out of the nose.

Try using humidifier in your room, and try to sleep slightly upright a bit or sideways.

Suggest you dont wait longer and quickly visit an ENT specialist. They will be able to diagnose this quickly and provide solution immediately. I know of one case, it was tonsil issue, only happen at night due to sleeping position and gravity makes the tonsil sit in a position blocking the airway. But due to left too long unattended, it affected other organs due to shortness of oxygen to vital organs and insufficient sleep. Dont wait.

It only worsens eventually. Some even get into accidents due to slept off during driving. One of the top specialist in Malaysia is Dr Balachandran Appoo, Specialty
ENT, Head & Neck Laser Surgery, in Thomson Hospital, Kota Damansara. Hard to get an appointment with him, but if u can get, see him as soon as you can. He does laser, so recovery is fast.

you have sinusitis, the dry air irritates the sinus and causes inflammation hence blocking air flow through your nose.

1. turn off air con when the air is cool enough for you to sleep.
2. add humidifier because the dry air is the cause of this problem.
3.  set a higher temperature for the aircon and test whether it works so that the air wont' be too dry and irritates your sinus. every  individual is different.

its quite a common problem. but only some people's condition will only get worse.
I had an Endoscopic surgery due to this issue cuz it went from bad to worse but that's the last resort.

i do too. its actually very common problem because of cold. use vicks or yuuyee or something. not minyak cap kapak coz too strong will give bad effect. try not to make too cold.

whats the temp u set?
if inverter set to 26 or 27