I am sorry to hear you are worried about Nikki. My name is Rebecca. I am a veterinarian and will do my best to help.
What kind of exotic cat is Nikki?
When an older cat is eating less, and not grooming, that tells me they are not feeling well. It could be many things: chronic kidney disease, pancreatitis, heart disease, infection, pain, and unfortunately) cancer. Licking her lips could be nausea, or it could just be her liking at the discharge from her nose. The runny nose could be a viral infection, bacterial infection, a polyp in her nose.
If this is a "cold" she might have a fever and that could cause her not to eat. Can you take her temperature?
If you look at her gums, do they seem pink in color?
At her age, I would have her checked by a veterinarian as soon as possible. Until then try to keep her hydrated by offering water, milk, tuna juice, broth. You can try children's nose drops like Little Noses for the nasal discharge.
Let me know what other questions you have, and if this was helpful.