I have a one year old female Calico Cat.

It has been Spayed.

It has the habit when curling up beside me of rubbing its nose and cheeks against my hand and ever so gently nibbling my hand every so often.

This is not a bite.

Very little pressure is exerted by the cat.

Whaaaas Up?

Tks. Dave Connor.

Your cat is claiming you as hers, she is saying you belong to her, (O:

Smell is an extremely important sense in cats, in some cases more than sight. Cats have scent glands on multiple places on their body including their faces and feet. On their face, the glands are located around the eyes, below the ears, and on the chin. By rubbing their face on various objects, such as legs and furniture, they are leaving their scent. Other cats passing the object will often stop and sniff, maybe even rubbing their faces on the object to leave their scent as well.

Scent marks contain molecules called pheromones. Different glands secrete different pheromones which affect a number of behaviors, including reproduction and establishing territory.

Rubbing Against Legs & Furniture
(http://www.peteducation.com/article.cfm?cls=0&cat=1276&articleid=1132)

In addition to the good answer by Lilfyre, I found that the love nibbles are an attempt to initiate grooming by watching my two cat brothers closely. So when they did that to me, I tried a cat brush on them. They loved it! And they purr and make the most exquisite cat-bliss faces when I do it. They still tell me when too LOL. Just a thought I hope is helpful.

I call those "Love Bites". Cute until they want to do it to your nose! Lol:)

One of my cats is the same way. If you scratch her in the right place she'll begin to nibble your arm so hard she'll actually break the skin sometimes. Of course, then she'll lick you vigorously afterwards, just to be sure to spread a few germs into the wound. :)