The easiest way is to take medications in order to stop your nose from running, preferably antihistamines. You will find pill bottles and nose sprays in the aisles of your local drugstore. Look in your medicine cabinet to find a bottle or two lying around.
Or, alternatively, you can just plug up the nose. If you have tissues lying around, keep the nostrils plugged up to block the exit of thin, watery mucus. It is a fast and temporary solution to an irritating problem.
Also, you want to blow your nose often to remove buildup mucus. Keep the nose clear for as long as possible. This solution lasts for at least an hour before the nose starts to run again. Take this step if you cannot find the cold medications anywhere in sight.