I was hoping to get some additional information from you, but I can send your answer now, so you don't have to wait any longer.
The source of this itching on your cat's nose must be determined. Ask the vet to do a skin scraping (painless) of the area and either look at it under a microscope and/or send it to a lab for testing.
The itching could be caused by environmental and/or food allergies or external parasites like fleas and mites. Even if you don't see any fleas, all it takes is the bite from one flea, to cause the allergic reaction.
If you use scented candles, incense, air fresheners, have a smoker in the house, used a new laundry detergent or fabric softener, or a specific cleanser, these are some environmental causes for allergies
Food allergies can be caused by soy, corn, wheat, gluten, carrageenan, artificial flavors, colors and/or preservatives found in your cat's food. Try to feed a grain-free food, where real meat is the first ingredient. Some cats are allergic to the protein source (meat) in their food, so you can get a food with novel proteins like duck and rabbit. Royal Canin, Blue, Natural Balance and many other companies make Limited Ingredient Diets (LID) foods, found at pet supplies stores, vets offices or can be ordered online.
If your cat spends time outdoors, her nose could be getting sunburned, especially if it is a light color. There are sunblock products that can be safe for cats; discuss this with your veterinarian.
You can find a soft E-collar in your pet supply store, to keep her from scratching at her nose. If that is not big enough, she'll have to wear the hard 'cone.' You can even fashion one yourself, from cardboard:
I hope all will be well with your kitty!
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