Is it possible to disable or skip nighttime in Horizon?

No, there is no way to fix or manually change the day/night cycle. Many people have commented on that in various threads, such as this one:

There doesn't seem to be a rest option that we are used to. The only thing I've noticed is when I hit a Campfire to save. There is a bit of a cut off during the manual save as well as if you incurred any damage it seems to replenish lost health. Spoiler. Other than that no I haven't come across any way to actually rest/fast forward the time cycle.

As well as this thread:

Don't think you can. I haven't come across any daytime restricted activities tho so it doesn't matter.

For what it's worth, during the 50-60 hours I played, I was also unable to find any way to manually alter the day/night cycle.

If you play on pc you can just go to a campfire and keep pressing quick save like 10-15 times. You don't need to wait the fade in-out effect, just press same button like 2-3 times per second and it fast forwards whole night.