There are no difficulties with this — the spacesuit is equipped with everything necessary, including the ability to scratch the nose.
Inside the spacesuit, there is a Valsalva device, which consists of two small soft pads.
In fact, this device is not intended for scratching the nose, but serves to equalize pressure in the cavities of the skull — as the astronaut experiences changes in air pressure when transitioning in and out of the spacesuit.
Divers refer to this procedure as "ear clearing," and it can also be helpful when experiencing ear blockage during airplane descent. Therefore, if the nose itches inside the spacesuit, the simplest solution is to use this handy device for scratching.
