As long as the discharge from the nose isn’t thick, pastey, or an odd colour. Such as yellow, white, or cream coloured you should be alright. I defiantly agree with Caoimhe though and you should run it by with your vet. Hope this helps!
What country are you in? If you are at all worried about your horse, ring the vet. This is not the place to seek medical advice as you would likely get well meaning but incorrect information.
It is VERY windy today and its the first day I have noticed it