Rashi: The anger of Resha'im causes that people thank Hashem, when they show their anger and Hashem exacts payment from them. All praise Him, and even the Resha'im themselves, when they see that their anger is nothing. We find that when Nebuchadnetzar threw Chananyah, Misha'el and Azaryah into the fire, he said "Brich Elakahon Di Shadrech" (Daniel 3:28).

Radak: The people who gathered against Yerushalayim for war, and their anger was against You, they will be forced to thank You. Their anger will revert to be thanks.

Malbim: (a) People's anger will praise You, for You have the power to stop the remnant of hatred; You do not arouse all Your hatred, unlike people. (b) Via man's anger, and the anger of Sancheriv, who wanted to destroy everything in his anger, Hashem stopped the remnant of His anger, and did not send Sancheriv further to destroy nations and kingdoms.

Rashi #1: Via this (Hashem exacting payment from Resha'im who show their anger), other Resha'im are withheld from showing their pride and anger. Tachgor is an expression of holding back, e.g. 'a nick in a knife [disqualifies Shechitah] if it is enough for a fingernail [moving along the blade] to get caught in it' (Chulin 17b-18a).

Rashi #2: Tachgor is an expression of girding. It is proper for You to gird Yourself with anger and wrap Yourself with envy, for You have the power and ability. It says "She'eris" because man's anger is nothing, so all girding of anger is to You.

Radak: When You will do the great vengeance against Gog and Magog, the rest of the nations will be girded with Chemos - they will fear You, and have no more hatred for Yisrael.

Sha'arei Teshuvah 4:12: When a sinner is afflicted, and he justifies the Din against him, and accepts it with love, this protects from "She'eris Chemos" - many afflictions that were proper to come on him. "Tachgor" - You will block them from coming on him.