As advised, your cat is making its pack position known - you are pack leader and your cat is being submissive to show that she knows that - the clawing abd nibbling are similrly friendly gestues, you'd know if she meant it!
Give her lots of affection and stroking - behind the ears and the shoulder blades are favourite places. Rub the bones in her back gently, she'll enjoy that too, as you will hear.