Why does it say "Nora" (singular)? Ma'asecha is plural!
Rashi: Each of Your deeds is awesome.
Why do they express His awesomeness?
Radak: He brought a weak nation out of many mighty nations.
Malbim: One must fear Him (and not only honor and praise Him), for He also conducts, oversees, rules and does like His will.
Why does it say "b'Rov Uzecha"?
Rashi: When You show to the world Your strength via a plague, the sword, hunger or lightning.
Radak: Due to this, they will [fear] and deny, and say that they did not harm Yisrael.
Malbim: The heretics say that due to Your greatness, You are elevated above all desire and intent; therefore, conduct of the world is via the Ma'arachah. Menasheh erred like this, therefore he worshipped the Heavenly legions, and denied Hashem's Hashgachah.
What is the meaning of "Yechasheshu Lecha Oyvecha"?
Rashi: Amidst fear, Resha'im will admit to their denial and Aveiros.
Radak: Refer to 66:3:3:2.
Malbim: Your enemies, the heretics, deny You, and say that the world is Kadmon (always existed), and it must exist, and You do not know what happens in it.