I expect the majority of cat owners to know the answer to the question in the title but (a) as the question is asked on the Internet and (b) it is useful to spell out the reason for the sake of clarity, I discuss the topic on this page.
There will only be two reasons why your cat touches your face with her/his nose. Touching noses is a greeting behaviour. It is most often seen between cats who are friendly towards each other (“preferred associates” in technical jargon). Females and males are equally likely to touch noses with the same or the opposite gender. Therefore the degree of friendship between cats determines whether they touch noses or not and the gender is not a determining factor.
Therefore, if your cat touches your nose with his nose then (a) he is treating you as a friend and (b) is greeting you. It is a pleasure for humans to experience this act of domestic cat behaviour.
If your cat touches an area of your face other than your nose then he/she is probably simply sniffing you. She is sniffing your scent. That would simply be out of interest as cats use their sense of smell all the time to “see” things.
The first reason is by far the most common reason why a cat would touch your face with their nose. It must happen all over the country all the time. If it does not happen in your household I would be a bit surprised to be perfectly honest.
If your cat does not touch your nose with their nose then it may be because they are a little bit fearful of placing their head so close to yours. From me, it’s a question of size differential. Cats are naturally cautious and humans are much larger and therefore the default position for a cat is to be slightly cautious even, sometimes, with their human caretaker but of course it depends upon the caretaker and the cat’s character. A reasonably confident cat and a loving caretaker who creates a good environment for their cat should experience the nose-to-nose touching behaviour on a regular basis.
P.S. The question in the title is not exactly how I would ask the question but as it is one that is asked by a lot of people I have used it. My preferred wording would be “why do domestic cats touch noses with their owner?” Or something like that I think would be preferable and more precise.