Why does it say "Oyvav Albish Boshes"?
Radak: This is opposite to "Albish Yesha" (16) for Kohanim who serve Hashem and pray for the king. I will clothe the king's enemies with shame.
Malbim: The horn that will sprout "Amim Yenagach Yachdav Afsei Aretz" (Devarim 33:17).
What is the meaning of "Yatzitz {Nizro}"?
Rashi: He will illuminate. This is like "v'Notzetzim k'Ein Nechoshes" (Yechezkel 1:7).
Ibn Ezra: It will emerge and be seen. This is like "Metzitz Min ha'Charachim" (Shir ha'Shirim 2:9).
Radak #1: It will sprout; [the king's] grandeur and beauty will grow each day.
Radak #2: This is like "v'Asisa Tzitz 1 Zahav Tahor" (Shemos 28:36).
Malbim: This corresponds to "Arachti Ner li'Mshichi" (17). Kings were anointed [via putting oil] in the form of a Nezer (crown). The oil Yatzitz Alav (will be like a Tzitz on his forehead - PF).
I.e. this refers to wearing an ornament (crown), just like the Tzitz is worn. (PF)