In this text there's no encouragement to sin - from God's part - to Pul (Tiglath-Pileser) of Assyria. This man was utilized by God as one of many instruments He utilized to give punishment to men deserving it, in this case, the rebellious sons of Israel.
Interestingly, God did punish Assyria too because it performed this divine assignment not with humility, but with "arrogant heart" and "haughty looks", as Isaiah 10:12 says. With a striking comparison, God continued to say: "Should the axe [Assyria] boast itself against him [God] that heweth therewith? Should the saw [Assyria] magnify itself against him [God] that moveth it? as if a rod [Assyria] should move them that lift it up, or as if a staff [Assyria] should lift up him [God] that is not wood." (Isa 10:15, JPS; compare with v. 24)
This way to do things is a peculiarity of the Creator, revealed throughout the Bible.
For an other example of this divine behaviour, we may say that in the not too distant future, they will be accomplished the prophetic statements of the Lord Yahweh reported in Rev 17, regarding the 'great prostitute, Babylon the Great', by means of the 'ten horns' belonging of a 'wild beast'.
Even if the Chronicles account spoke about a divine punishment against his own people, whereas the punishment reported in Revelation was toward an enemy of Him, the basic 'stirring'-concept is the same (bold is mine): "And the ten horns that you saw, they and the beast will hate the prostitute. They will make her desolate and naked, and devour her flesh and burn her up with fire, for God has put it into their hearts to carry out his purpose by being of one mind and handing over their royal power to the beast, until the words of God are fulfilled" (Rev 17:16-17, ESV).
I hope these short notes will be useful to your research.