It can be an interesting practice to just observe the feeling. Resist the temptation to act upon the impulse immediately. Create a space between the perception and the reaction.
On the other hand, if you have a flu or something, it can be more distracting (and messy) to keep feeling the nose running than to actually clean it up. It can be a good idea, in these circumstances, to have some tissues near you, so if you do need to wipe your nose, you do so mindfully, and with the least amount of movement.