What is the significance of a ring on her nose?
Rashi citing Targum Yonasan: I gave an Aron of the Bris between us.
Malbim: This refers to Mitzvos that depends on the eyes and the sense of smell. Smell hints to spiritual sight ? "va'Haricho b'Yir'as Hashem v'Lo l'Mar'eh Einav Yishpot" (Yeshayah 11:3). The rings on the ears hint to Mitzvos that depend on hearing.
What are "Agilim"?
Rashi: They are rings.
Rashi citing Targum Yonasan: The cloud of My glory stands over you. Rashi - they are called Agilim, for [Yisrael] were surrounded in an Igul (circle).
What is the crown on her head?
Rashi citing Targum Yonasan: An angel sent from in front of Me speaks at your heads ? "va'Ya'avor Malkam Lifneihem va'Shem b'Rosham" (Michah 2:13).