I would say the metaphorical phrase would be “I drank in the beauty of nature, a delicious treat” because nature is being compared to a delicious treat, BUT a metaphor does not contain the words “like” or “as”, like a simile does.
For example, “The tulips were bright slashes of color like a child’s crayon” is a simile because it is comparing the tulips to a child’s crayon, but it employed the word “like”.
Hope this helps