Did you read Tomer Devorah's post about the number 50? The letter Nun is the number 50.
I remembered I did have a post about the letter Nun, although I hadn't published it, it was there waiting as a draft. Here it is.
"It is written in the Gemara [Berachot 57a] that one who sees Huna in a dream will have a miracle happen to him. If he sees Chanina, Chananya, Yochanan, or Nisi, many miracles will occur. However, this applies only if he sees these names in writing. Rashi explains that all these names contain the letter nun, the first letter of the word -- miracle." [Source]
By focusing on the letter Nun, it can bring you from a state of darkness to a state of joy, and to see miracles.
Perhaps we can explain this based on the Gemara in Berachot [57a] which says that one who sees the names "Chanina, Chananiah, or Yochanan" in a dream - "nisei nisim" (wondrous miracles) were done for him.
Rashi explains that all of them have a double nun, alluding to "nisei nisim," many miracles. The Maharsha explains differently, however, that a name defines a person, and all of these names have either a yud-hey or yud-vav and the letters "chen." The base of these names, therefore, is that the person finds "chen" (grace) in the eyes of Hashem.
All of these people recognize even in natural, mundane events the goodness of Hashem. The Ramban at the end of parshat Bo [Shemot 13:16] says that a person does not have a share in the Torah of Moshe Rabbeinu unless he believes that everything is a miracle. We say three times a day, "for your miracles that are with us every day." [Rabbi Y. M. Schachter]