Firstly, remain calm. If you panic, then your child is more likely to panic too and make both the situation and the discomfort worse.
Assess the situation. If you can see the object and it’s low down the nose then try to remove it using the tips above. If it’s higher up, you can’t see it at all or it’s a button battery then attend your medical center immediately which is much better placed to help with all the right equipment.