Nobel is a proper noun. It is the surname of the inventor and businessman, Alfred Nobel, who set up a trust from his earnings from the invention of Dynamite and instituted prizes for disciplines like Physics, Chemistry, Medicine & Literature. Later a Prize was introduced for Peace and Economics. All these prizes are known as Nobel Prize. And the winners of these prizes are entitled as Nobel Laurette.
Noble is also a noun and describes a persons loftiness, Impressive in appearance, or belonging to Aristocracy.

Nobel is a name

noble means Belonging to a hereditary class with high social or political status; aristocratic., A person of noble rank or birth.